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The magazine for Sinclair users and TIMEX /Sinclair users

—À— JU

| July/August 1983

Volume 3, Number 4

| BUYER'S GUIDE: PART II

| SYNC AT THE WORKBENCH: Robotics on a Budget: Build a “TS 2000"

| Connect a Monitor * Add a Counter * Add a Joystick ° Hardware Tips
MACHINE LANGUAGE: MC and your TV Screen ° REVIEWS: Votem

|
|

Dj 7;

554

14024714

SPEND
MORE TIME

WITHYOUR —
TIMEX ——

Action-packed new computer games. Time-saving
| home and business software. Add-ons to make your SOFTWARE

Timex more versatile and powerful than ever before.

| These are just a few of the reasons you'll be spending GAMES
| a lot more time with your Timex once you discover REQUIRE 16K sak eae sue
| Data-Assette — products developed specifically for ( Q ) D c

| your Timex/Sincloir Computer. e Great Western Hit

the trail to adventure as

| ou make the decisions [. " a re
| RDD-ONS that will spell survival or — toarna:

| disaster in the great
| l , , outdoors. Price: $19.95 :
| Here are the accessories that will make your Timex as powerful e Time Trippers VIDEC
| and versatile as computers costing lots more. Expand Take a trip through :
| your meen Simplity loading and copying. All without break- history as you work to
| ing your budget. patch tme-bending
| oles that riddle the
e ZX-99 TAPE CONTROL UNIT universe. hea adven-

PEDES MA Advanced data processing features at a ture at its best. Price:
ae =: AA fraction of the cost. Mass storage. Save, $19.95 S

load, and merge files. Interface with e Gobble A fast-moving maze game that simulates the origi-
any serial printer. Automatically contro! nal. Players can advance to ten different levels of difficulty for a
Up to four cassette decks. Price: $99.95. real challenge. Price: S] 9 95
|
| © PERFORMANCE IMPROVEMENT SYS- ENJOYABLE LEARNING
| TEM No more tape headaches. Sets record and e Micro Music (requires 32K) Converts your computer key-
| layback levels precisely. Checks head alignment. board into a musical one generating 43 musical tones (31/2

octaves) that can be heard through headphones or your
cassette player. Price: $9.95

e ZX Compiler Convert your ZX-81/TS-1000 BASIC pro-
grams to machine language. Increases execution speed and
teaches you the nuances of compiled programs. Price: $24.95

ncludes an in-depth book on the use of cassette
recorders with microcomputers. Price: $29.95.

e RAM EXPANSION PACKS The fastest, least |
expensive way to add powerful memory expan- |
sion to your Timex. Designed so they won't

shake loose. 16K Unit: $39.95 32K Unit: $89.95

Ask for Data-Assette software and add-ons at your
64K Unit: $149.95

computer dealer. For further information, call Data-
Assette (1-800-932-4807) or send $2.50 (creditable

e POWER SUPPLY Foil that flicker and fade. A full one amp toward purchase) for a complete catalog of Data-
will support a host of peripherals. And a convenient on/off fissette products. And plan on spending alot more
switch for easy power-up/power-down. Price: $19.95 time with your Timex.

| | WATCH FOR NEXT MONTH'S NEW RELEASES

n ou TS

56 South Third Street, Oxford, PA 19363

THE MMINDUUARE Line or SOFTWARE
FOR TIMEX/SINCLAIR COMPUTERS

MATRIX THE FAST ONE Z-TEXT INVENTORY FORECASTING

PLANNER Store, organize Ausefulword CONTROL GRAPHS

An all-purpose and retrieve processing Two ways to Analyzes

electronic data instantly. program. keep track of growth

spreadsheet. $24.95 $19.95 inventories. trends and

$22.95 $22.95 plóts graphs.
$22.95

ENS | om- |

MONITOR GULP LABYRINTH PILOT GRAPHIC GOLF
Tests and Gobble your Can you find Cockpit A challenging
debugs way through your way controls 18-hole
programs in mazes,chased through thatteach you golf course.
machine code. by ogres. 3-D corridors? howto $9.95
$19.95 $15.95 $15.95 navigate.

$19.95

SCREEN KIT

SLIDE SHOW CRITICAL NUMERIC TOOLKIT

Creates and PATH Solves math Shortcut Routines to

runs video Gets complex formulas and commands for enhance

display shows. scheduling draws graphs. programmers. screen

$22.95 under control. — $24.95 $19.95 displays.
$19.95 $19.95

CROSSWORD ANAGRAMS WORD TEST MULTIPLE COSMOS
Create and play Try to put the All kinds of CHOICE Hyperspace
your own scrambled question and Can you pick laser battles
crosswords. words answer tests. ^ the correct among the
$15.95 back in order. — $15.95 answer? stars!
$15.95 $15.95 $15.95

@ FAST LOADING Mindware's proprietary
Quickload™ feature lets you load
programs up to four times faster
than conventional Timex/Sinclair
programs. Quickload software also
alerts you to misloads, and lets you
restart the tape from the point of
interruption, without re-loading from
the beginning.

THE ONLY PLAIN PAPER, DOT- MATRIX
PRINTER FOR THE TIMEX/SINCLAIR SYSTEM

Mindware's MW-100 gives you the
ability to make hard copies
of programs, data, mailing
lists, and screen

graphics.

SPECIAL OFFER: Ordera MW-100 printer for $119.00
and get your choice of any two Mindware software titles
FREE; plus 5 FREE rolls of paper (comparable retail value,
$150-182.00).

Thousands of MW-100's have sold nationally at a retail price of
$129.95 (Printer alone).

e QUALITY TITLES Mindware software is
written by top British software
developers, including Picturesque,
Hewson, Hilderbay, Asher, Campbell,
Axis, Jones, Vortex and Silversoft.

e USER-FRIENDLY Documentation provides
clear instructions, learning examples,
and trouble-shooting tips.

(All programs require 16K.)

SOFTWARE ORDER

2.25

Postage & handling
Total
(Mass.residents add 5% tax

SPECIAL PRINTER OFFER - Retail value, $150-182.00
MW-100 printer - 119.00
Two software titles free: N/C
N/C
4.95

Postage & handling
Total
(Mass. residents add 596 tax)

Total enclosed is O check O money order
Charge to [] visa [] Mastercard :
Mns Volume discounts
; ' available to dealers
Expiry Signature
| Please Print and schools.

Send more info on:
O Quickload software.
L] MW-100 printer.

SEND TO: Eagle Sales Co./SY
15 Tech Circle Natick, MA 01760
(617) 655-3368

Na
| Address
i City/State/Zip

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21st CENTURY ELECTRONICS

THE FORTH CORMER - —

Zen FORTH : kaga 25 ree d dug

La cassette GUTTE BERG N. J.
MULTI FORTH #49, 95 | 7093

oe er — L TELE. ( 201 0869-2616
(bw lea brodie? — — B SEND CHECK OR MONEY
HARD COVER $22, AE EJ E a ORDER OR CRLL FOR
SOFT COVER 4. Rt "€ LL C.Q. D s

zhiPPins and handling $1.36

- => € C
T/S 1000" PERSONAL COMPUTER ** *-* 49.95

TIMEX SINCLAIR" PERSONAL PRINTER 89.95

E-—-— KEY HHREYvEOFBFD 84.95

L&G YU-LOAD MONITER 20.95 |
EEXCEEEEEYEREXEEREEEEXKKEREXXIZRkEXttrpkbbbbkkkkkbbbbbbbobbboboobooooon ono

y ey aeecernys deo phere 21st CENTURY ELECTRONICS

—— SHLESDRTH 2E
; uU du CH : ‘ eee UE SY .— fri CENTURY SALES REPORT @

THIS IS A TRUE SALES DATA AND ANALYSIS PROGRAM. OWE, THAT IS
COMPLETELY USER FRIENDLY. THERE IS HO SETTING UP OF A FORMAT, TO f a NEHUE B
prp una AA MAKE THIS PROGRAM WORK. JUST PUT IM YOUR OWN COMPANY MAME. THE
YEAR AHD THE GURRTER YOU WILL BE USING THIS PROGRAM FOR, AND "fU (1° ENTER STARTUP DATA
32k 93.35 ARE READY TO START PUTTING IN DATA. CARTER STARTUP DATA HAS BEEN 23
16K 49.95 EVEN WITH ALL THE POWER AYALIABLE IM THIS PROGRAM, WE HAVE CENTERED DO HOT PRESS WO. 1 OR >
HI RES 99.95 BEEH ABLE TO PUT IT INTO 16K SO THAT YOU CAN USE IT WITH THE CYOU WILL LOSE ALL THE DATA YOU?
GRAPHICS BASE SYSTEM. — (HAVE ENTERED ?
MEMOCRLC 99.95 THE PROGRAM COMES WITH FULL DOCUMENTATION AND IS MENUE DRIVEN, ; ENTER CATA
R uy L OR C G RO - scar, WEEK Yor
PRINTER 399.95 ME HAVE PUT A FEM ERROR CORRECTING ROUTINES IM IT, TO MAKE THE PEAD WEEKLY TOTAL
AND

4 PROGRAM EASIER TO OPERATE. REAL TOTAL SALES TO DATE
* INTERFACE

a x

WHEM YOU PLRCHRSE THIS PROGRAM, OJ HOT ONLY GET THE PFRÜGEHM CALL CUSTOMER RECORD
ELT YOU MILL BE PUT OH OUR PREFERRED LIST. ENABELING YOU TO TO SAVE DATA
RS232 99.95 GET ALL UPDATED VERSIONS OF THIS PROGRAM FOR A HOMIHAL FEE. ‘fo AOD A HEM CUSTOMER
INTERFACE WILL ALSO BE ABLE TO PURCHASE AMY OF OUR FUTURE BUSIMESS PRO- SEARCH LAST YEARS RECORDS
PARALLAL 74 95 GRAMS AT A DISCOUNTED | RATE, WITH OUR FUTURE PROGRAMS ‘VOU HILL BE FIND AMOUNT OF MEMORY LEFT
i ABLE TO PUT TOGETHER A FULL BLOWN BUSINESS OH YOURE TIMES- 1006. READ CUSTOMER LIST
INTERFACE aue
KEYBOARD 99.95 Zim CEHWTURY S EL.EICTFEOE LIC
SALESOCATA E
X 808 CCRCRCORON IC RORORORONOROROROIOKOKGOE ECCO E — e. cU a:

KKKKKKKEKEKEREARA EERE EEE EREKE ERR ETRE RARER EE + uuo ECOLE EO E 4K KOK: unii eda ries
* FLOPPY DISK INTERFACE FOR TIMEX BUS $152.00 € i: F TWARE +
* POWER AND CABLES FOR 2 DRIVES $ 69,80 X com TS roo Su Se
* DOUBLE SIDE-DOUBLE DEHSITY FLOPPY DISK DRIVE 4 SKA ACK AR EE AEE AOE
x $198.95 X XAOEKGRKOROKO EE E MID #16. 25

* WORD PROCESSING SOFTWARE PACKAGES DISK 0S 35.804 MIGHT GUNNER
EXEXKEKEREREREEEEREREREEREREREERRERE ERE R ERE ERE E$ SUPERCHESS
dokoccobcoepbolccooo bp bec ee ppc cp pe pec pepe bee *EEXEREXXTLLEEREXX
+ HUMTER SK HOM VOLITILE MEMORY KIT $22. 95 +
* BARE BOARD W-MANUAL 3,45 *
+ ASSEMBLED BORED WSK CMOS RAM 54.95 +
x S. and H. $1.95 $
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FOR IHFüRMRHTIOM OF PRICE OW THE TIMER. a8 CRLL OR WROTE

D pepqpeneanna

The Magazine for Sinclair users and Timex/Sinciair users

ExL Iri ll

July/August 1983

DEPARTMENTS

ToSXNDNOIOE ie e ree eer Docs Grosjean
TID Gilteboidz Report. |. 2... a ood oh Lex oe
PL TES 03S rs see Brodsky, Chandler, Marasa
85 JustforFun.................. Adams, Koenig, Schultz

Te Porcontions.; o sse ise Sb e A Ornstein
INPUT, OUTPUT, and Other Confusing Things

77 Timex Developments........................ Grosjean
120 Index to Advertisers. ......... ooo
SYNC AT THE WORKBENCH

18 Robotics on a Budget........................... Taylor
Your TS1000/ZX81 as a controller

32 So You Wish You Had Bought a TS2000.......... .Day
Color, sound, and a joystick on your TS1000/ZX81

50 ConnectaMonitor............................. Lewart
One transistor

52 A Joystick for the TS1000.................... Stephens
Adding an Atari joystick

5G 2K-4K Upgrade. i... F o bo G Glidden
Expanding your RAM

Staff
nounder(paditord Chief. eo eA ee ee POS. David Ahl
OR EY MTT UTS) SS a Se la ete E Sota ie S.S Te Paul Grosjean
DB PION, Doo a. OA a) EE David Ornstein
DN CONESDOBRMENE T SC Pe Ot EI. Martin Wren-Hilton
ACEDER Y OUS haud S ENCIMA LCS ICE Patrick Calkins
Assistant AT DIEC CON Cl n os o ghee hA Diana Negri Rudio
DONORUM DUUM VEA VEMM ely ITEM cede eee lr EE] Karen Brown
Operations Manager.............................Patricia Kennelly
PUNEN COES eed aora ode LA ce a VeL REY un Frances Miskovich
qo quos c. ree Me ie Ne tanh te ce E EE, Welk, glide cal ge SNe c Carol Vita
Advertising Sales Manager... 2: bee ee os Karen Musmeci
Advercung Coordinator. ^..70072 50 uses TDI Claudia Reinhardt

SYNC Magazine is published by the Consumer Computers and Electronics
Division of Ziff-Davis Publishing Company.

OSE or va es ee ever. dues Eo Seon Rae WE President
Beer renee. a a RIEN Vice President, Marketing
Eileen G. Markowitz................ Vice President, General Manager
ENEMIES. eLLS us toes ae e A Creative Director

Volume 3, Number 4

92 Adding a Counter in Hardware................. Puerzer
Keeping time

PROGRAMMING TECHNIQUES

66 Stringing along with the ZX81................. Wentlink
Using READ and DATA

74 RUNning with Reduced RAM.................Hartung
Save time by lowering RAMTOP
MACHINE LANGUAGE
86 Machine Code and Your TV Screen............ Doakes
Introduction to machine code, part 3
REVIEWS
/6-TheVotem:- uuo ol roues o EE Kelly
Hardware review
78.Memopak HRG = 2. oso S suh Herriott

Hardware review
BUYER'S GUIDE SUPPLEMENT
80 Directory of Suppliers... ..... L.L sse
100 improving Your Computer.............................
100 Extending Your Computer.............................
Programming Your Computer.........................
Using Your Computer: Programs.......................

Enjoying Your Computer: Games......................

Volume 3, Number 4

SYNC (USPS: 585-490; ISSN: 0279-5701) is published bi-monthly by Ahl
Computing, Inc., a subsidiary of Ziff-Davis Publishing Company. David
Ahl, President; Elizabeth B. Staples, Vice-President; Selwyn Taubman,
Treasurer; Bertram A. Abrams, Secretary. 39 E. Hanover Ave., Morris
Plains, NJ 07950. Second class postage paid at New York, NY 10001, and at
additional mailing offices.

Permissions: Material in this publication may not be reproduced in any
form without permission. Requests for permission should be directed to
Bette Amado, Ziff-Davis Publishing Company, One Park Ave., New York,
NY 10016.

Subscription rates: USA: One year (6 issues), $16; two years (12 issues),
$30; three years (18 issues), $42. Canada: $3 per year additional. Other
foreign: $5 per year additional.

For SYNC advertising information, contact Karen Musmeci, SYNC
Advertising Sales Manager, Ziff-Davis Publishing Company, One Park
Ave., New York, NY 10016 (phone: 212/725-4216).

All other correspondence should be addressed to: SYNC, 39 E. Hanover
Ave., Morris Plains, NJ 07950. In U.K. to: SYNC, 10 Bishops Way, Sutton
Coldfield, W. Midlands B74 4XU.

Postmaster: Send address changes to: SYNC, PO Box 789-M, Morristown,
NJ 07960.

£x ee ee ee a a rt le st ae a T dS E a NE et E KL EUREN TN S C s.

July/August 1983 ° SYNC

Your computer can prob-
ably do more for you than
you originally thought.
And learning to expand its
capabilities is as easy as
reading a good book.
SYBEX is the pioneer
of computer book pub-
lishing, offering over 60
tiles developed for begin-
ners through advanced. They are so well

written and easy to understand that virtually

anyone can learn to operate a computer
in a matter of hours.

Your Timex/Sinclair 1000"
and ZX81 by Douglas
Hergert ($6.95) Learn
the ins and outs of your
Timex/Sinclair 1000” You
can learn how to connect
the computer to your
television set, program it,
perform math, make bar
graphs and play games.

YOUR _.
| CLAIR
TIMEX SINCLAIR

ANE RES

will find clear descriptions, proper syntax

and examples of every keyword and function
in the Timex/Sinclair 1000" BASIC vocabulary.
Timex/Sinclair 1000" BASIC Programs in
Minutes by Stanley R. Trost ($7.95) Get the
advantages of programming your Timex/
Sinclair 1000" without having to learn how to
program. This collection of BASIC pro-
grams allows you to: calculate home finan-
ces, analyze business and personal invest-
ments, investigate real estate
options and much more.
More Uses for Your Timex/
Sinclair 1000:" Astronomy
on Your Computer by Eric
Burgess ($8.95) Stugy the
stars and planets in your
own home. The ready-to-
run programs allow you to
observe constellations,

The Timex/Sinclair 1000" BASIC Handbook - — Wess
by Douglas Hergert ($7.95) This is-the. >:
indispensable computerside companion for...
programming your Timex/Sinclair 1000" You ':

stars, planets, meteor showers
and all that is celestial — on your
television screen.

SYBEX books are available
at bookstores and computer
stores everywhere. For a free
catalog, mail the coupon or call
TOLL-FREE 800/227-2346.
Prices subject to change
without notice.

Send me: L1 A free catalog
9 Your T/S 1000" and ZX81 $6.95
3 The T/S 1000" BASIC Handbook $7.95
9 T/S 1000" BASIC Programs in Minutes $7.95
2 More Uses for Your T/S 1000:"
Astronomy on Your Computer $8.95

Add: L1$2.00/Book UPS O 6596 Sales Tax CA Res.
O $12.00/Book Overseas Mail

Mail to: SYBEX Inc., 2344 Sixth St., Berkeley, CA 94710
© 1983 SYBEX, Inc. 17-5A 4

SYBEX COMPUTERBOOKS

letters

Loan Amortization

Dear Editor:

I would like to suggest two changes in
the loan amortization program (SYNC 3:1,
p. 30):

Add:

124 PRINT

125 PRINT “TOTAL PAID IS:#$”;P*'MO
Change line 145 to:

145 FOR I=1 TO MO

The “TOTAL PAID” line is useful in
comparing two different mortgage pro-
grams, e.g., a home loan at 13.5% for 30
years versus 12.25% for 15 years. The
change in line 145 makes the amortization
chart run with the length of the loan.
Len Parkin
12 Hughes PI.

Summit, NJ 07901

LOADing Problems

Dear Editor:

I have had periodic trouble with SAVE-
ing and LOADing with my ZX81.I went to
a negative ground cassette, thinking that
would help. But not too much!

Then I watched the output from the
recorder on a scope. As compared with
prerecorded tape, my tapes were relatively
noisy and errative and slightly fluctuating
in audio level. I then opened the recorder
and disabled the automatic recording level
control.

I have not had the problem since. It
gives you a good feeling to see a tape
LOAD without a flaw, especially when
you work two or three hours programming
for a file.

Phil Epp
5662 N. Seneca
Wichita, KS 67204

Ed. —LOADing and RAM pack wobble
seem to top the list of problems we hear

July/August 1983 ? SYNC

about. In our next issue we will gather
some of the suggestions for dealing with
these problems.

Mazogs

Dear Editor:

I recently acquired the Mazogs game
and found it to be one of the best I have
yet seen for the ZX81. I did find one
minor bug in it though. When the entire
maze is displayed at the end of the game,
the computer will crash if you scroll the
maze past the top or bottom border. This
can be remedied by rewriting line 1050 as
follows:

1050 LET X=X+(K$=“J”)-(K$=“H”)+
(K$=“S”)*64-(K$=“W”)*644+ (X=MST+
64)*64-(X= MST + 1504)*64

My congratulations to Don Priestly on
this excellent game and I will be looking
forward to more of his creations.

Glen Martin
Ultimatum

3470 McKinley Dr.
Abbotsford, B.C.
Canada V2S 6B7

Keeping Time

Dear Editor:

I have received several requests for the
seconds indication for the face clock in
my article in SYNC 3:1. This is one way to
add the seconds, but it requires more than
2K RAM:

230 FOR Q=3 TO 36
231 LET R=Q/23*PI
232 PLOT 27+18*SIN R,22+18*COS R
233 UNPLOT 27+ 18*SIN R,22+18*COS
R
234 NEXT Q
235 PAUSE 166
Another question was how to adjust the

timing of the clock. Here is how I do it:
Using WWV time or other accurate
means, time the clock for a full hour. Then,
if it is fast by 7 seconds, for example, add 7
to the PAUSE value. If it is slow by 12
seconds, for example, subtract 12 from
the PAUSE value.

Chuck Dawson

6520 Victoria

Ft. Worth, TX 76118

Ed. — The author also has developed two
machine code clock programs with sec-
onds. These require at least 16K RAM.
He will supply them on tape to anyone
interested for $10.

EPROM Programmer

Dear Editor:

I have a ZX81 with a Memotech 64K
RAM pack. The Memopak includes 8K
RAM which fills the transparent block of
memory from 8-16K. Since this area is
now occupied, is it still possible for me to
use the EPROM Programmer in SYNC
3:1? What, if any, modification is neces-
sary?

John Graf
12669 Mollylea Dr.
Baton Rouge, LA 70815

Dan Schaaf— There is a problem, but be-
cause each memory pack probably does
things slightly differently (and because I
do not have one ora schematic of one), I
do not know of a way to make the circuit
work without more specific information.
In principle, it would be an easy matter.
There is a probably a problem also with
32K packs. But I see no problem with 16K
packs since they do not address the ROM
space. I have also received letters about
my pin assignments. I would advise getting
the data sheet for the EPROM you buy
and then use its pin assignments. "n

Timex/Sinclair 1000

A T/S 1000 "PROGRAM"

10 IF YOU OWN A T/S 1000, A GOOD VALUE, GO TO 30

20 IF YOU DON'T OWN ONE, BUT ARE EXCITED ABOUT ITS CAPABILITIES
AND WANT TO BE INFORMED, GO TO 30

30 GO TO BOOKSTORE AND BUY THE TIMEX/SINCLAIR 1000 USER'S GUIDE,

VOLUMES 1 AND 2

User's Guide User's Guide

Timex/Sinclair 1000

Presenting another great value —
The Timex/Sinclair 1000 Series
by QUE

Whether you currently own or are considering
buying the T/S 1000, you'll find that these books
have lots of information and are easy to understand.
In short, they mean more value for your $ and more
exciting uses of your computer.

The books are not only informative, but often
humorous, and are loaded with programs,
illustrations, flowcharts, and alternatives for
accomplishing the most with your T/S 1000. Volume
2 gives information on accessories and games that
have been developed for the Timex/Sinclair 1000.
Both volumes contain several appendixes that cover
a variety of interesting topics.

The Best-Selling Timex/Sinclair 1000 Series also includes a quick-reference pocket dictionary and a
computer games book, Timex/Sinclair 1000 Adventures: Timelost. Look for them in all bookstores and
computer stores.

You can also use the coupon below to order directly from Que or call us toll-free (2 1-800-428-5351

Name

Timex/Sinclair 1000 User's Guide, Vol. 1 @ $ 9.95

Timex/Sinclair 1000 User's Guide, Vol. 2 (9
Timex/Sinclair 1000 Pocket Dictionary (2
Timex/Sinclair 1000 Adventures: Timelost (2

Total Retail Price
Add $1.50 per book for shipping and handling

$12.95
$ 4.95
$5.95

$33.80

SPECIAL DEAL: When you order a complete
set, you get all four books
for only $29.95.

Add $2.00 for shipping and handling on sets

Quantity

Indiana residents should add 596 sales tax
Address

City/State/Zip
Charge my [ ] visa LJ Mastercharge L] Other (specify)

Signature

Total enclosed $
Cudé a Dare

CLIC ” 7960 Castleway Drive, Indianapolis, IN 46250

EXLIDIT L. notes Paul Grosjean

SYNC at the Workbench

Our theme section “SYNC at the Work-
bench” focuses on hardware projects that
will enable you to control a robot, convert
your ZX81 or TS1000 into a “2000,” adda
counter and a joystick, extend your RAM,
and connect to a monitor.

Since some of these projects involve
opening your computer, remember that
this will probably void any warranty cover-
ing the computer. We also remind you
that such projects are undertaken strictly
at the builder's own risk. SYNC and the
authors of the articles cannot be respon-
sible for problems that may arise in at-
tempting these projects.

We know that many readers have never
tried a hardware project and that some
readers are experienced hardware builders
who can do a project with a schematic, a
parts list, and a few directions. Obviously,
not all projects can be done by the begin-

You won't believe the SPEED

D —-—-—---2-7-—

ner, but our standing request is that, when-
ever possible, articles be written so that,
when the person who has never tried a
hardware project looks at an article, he
will say,‘“That looks like something I could
do.”

We hope that you will enjoy these chal-
lenges of hardware construction and al-
teration.

Next Issue

The theme section for our next issue
will be “SYNC at the Library.” The section
will include as complete a list as possible
of the books available for the ZX/TS
computers in the Buyer’s Guide format,
newsletters, periodicals, indexes, some
general books on computing, and book
reviews.

We will also include a User Group list-
ing. We ask that all user groups drop us a
card giving the following information.

ae ZX PRO-FILE

E EA a

16K $16.95

Name of group; geographic area or interest
served; contact procedure (person, ad-
dress, phone where relevant); newsletter
name if any. Address your card: User
Group Listing, SYNC Magazine, 39 E.
Hanover Ave., Morris Plains, NJ 07950.

Buyer's Guide
Supplement

The response of entries for our Buyer's
Guide Issue was so overwhelming that we
did not have space for all the entries or
time to process them. We could not in-
clude several categories (Biorhythms,
Horse Racing, Golf, Hangman, and As-
tronomy). These categories and the re-
maining entries are in our "Buyer's Guide
Supplement."

The supplement follows the same for-
mat as the Buyer's Guide. The supplier's
name is given in bold face type; check the

Inventory Records
Personnel Files
Mailing Lists etc.

The just released, machine code updated

version of ZX DATA FINDER (below).

elnstant searches

e Printer compatible

eMulti-word searches eNumeric ordering

* Z-WRYTER — WORD PROCESSING

The ULTRA-FAST machine language arcade game for professional

gamesters. Lasar blasts. collisions. violent explosions. real-time
acceleration. aliens that fire back. and much more. all at a frenzied.

machine code pace. 16K $14.95

* TORPEDO ATTACK
* PHASER WARS

Complete statistics for every team in the
league. 3 versions, USFL '83, NFL '81 -'83,
NFL '82 -84. NFL covers two seasons. You

update weekly.

E».
Date Signature

July/August 1983 ° SYNC

16K $9.95
16K $9.95

* NFL ***** USFL STATISTICAL SUMMARY

16K $14.95
* EPHEMERIS V — ASTRONOMERS!! Gives
coordinates, sky charts, much more.

City

State Zip
Credit

Card No.

* EZ-HEX —

Write,
machine code hex programs.

* ZX DATA FINDER — Data handling fully
explained. 28 page tutorial manual.

* METAGRAPHICS —

$12.95

* PROFIT PLAN — Analyze 5 proposals, 30
variables each. A MUST for entrepreneurs.

16K $12.95
test, and save
16K $12.95

edit,

16K
$14.95
Draw and save any

graphic pattern with machine code cursor

control.

514.95

robotec, inc.
P.O. Box 55

Rossford, Ohio 43460

PHONE ORDERS WELCOME

419-666-2410

High quality cassettes

Fully Guaranteed
Dealer Inquiries Welcome

FAST DELIVERY
PROFESSIONAL SOFTWARE

16K $14.95
* CHECKSTUB

* GRAPH | & Il — 16K

— 16K $12.95

Shipping & Handling
Ohio Residents 5v? % Sales Tax
Total

IS INTERCOMPUTER INC.

Expands the use of your TIMEX SINCLAIR 1000

PROGRAMMING TOOLS

* ASSEMBLER/DEBUGGER "ZXAD" (16K RAM). Write
machine code quickly and easily with this professional quality
two-pass assembler. Using ZILOG mnemonics with labels
and symbols, 8 pseudo-ops, syntax checking, display or print
listing with commands. Debugger includes examine/modify-
ing, breakpoint with registers display, line renumbering occu-
pies 7K. Comprehensive multipage manual.

#PT 4003 $18.95

e STATISTICS PROGRAMS (16K RAM). Twelve programs
with extensive directions for entering data. All programs use
provisional mean formulas.

Book: 200 page Introduction

and listing. NEW #BK9001
6 cassettes: NEW #BK902

ENTERTAINMENT

#HM5001

(16K RAM).
#HM5002

#HM5003

(16K RAM).
#HM5004

$12.95
$17.95

* We offer up to 16% discount on our
packages.

* We have special prices and terms for
user groups, schools, colleges, stu-

* We pay for shipment for all orders
placed before August 31, 1983.

and more information.

e KRAZY KONG (16K RAM). A new version of the popular arcade game. This pro-
gram has all the features of the original and is every bit as fast.

#FG1013 $12.95
e HOPPER (16K RAM). Can you help Fergy and his friends get across the highway
and back to the Lily pond? Includes crocodiles, logs, varying-speed traffic, etc.
#1017 $12.95

e TAI (16K RAM). In any other time or galaxy, the dust ball of the world called TAI
would have been quite unimportant. Times change and the entire civilization will be
betrayed. You have been chosen to defend TAI. The Galactic future depends on you.

#FG1016 $12.95
e GHOST HUNT (16K RAM). Gobble your way through a maze of Ghosts, Power
Pills, etc., etc., very fast. #FG1014 $12.95

e MAZE DRAG RACE (16K RAM). Drive through a giant maze 9 times the size of the
screen; watch out for other cars, rocks, oil and ice. A really superb machine code
game. #FG1015 $12.95

EDUCATIONAL SERIES

e EDUVENTURE I (16K RAM). Answer the questions encountered in each classroom
until you make it outside for RECESS and the surprise that awaits you there. (Grade

level K-3) #ED3001 $12.95

e EDUVENTURE II (16K RAM). Each new situation requires either your ingenuity or
knowledge (or both) to avoid being sent to the principal's office. (Grade level 4-6).

#ED3002 $12.95
e EDUVENTURE Ill (16K RAM). Solve complex puzzles to outwit your teacher and
achieve the highest scores. (Grade level 7-9) #ED3003 $12.95

e EDUVENTURE IV (16K RAM). An agile mind and quick reflexes will get you
through this maze of mysterious situations — to your DIPLOMA. (Grade level 10-12)

#ED3004

$12.95

e CHECK BOOK MANAGER

* ADDRESS BOOK (16K RAM).

* OCCASION CALENDAR

dents, research institutes and libraries.

* Please write or call us for free brochure

HOME MANAGEMENT

e BILL ORGANIZER (16K RAM).

$14.95

Flexible Ribbon Connector

MEMOTEC PRODUCTS
MEMORY EXPANSIONS

e16KRAM #PL7002 $49.95
e32K RAM 8PL7003 $99.95
e 64K RAM $PL7004 $149.95
e HIGH RESOLUTION GRAPHICS
(16K RAM)
#PL7007 $99.95
e PLUG-IN KEY BOARD
#PL7011 $99.95
e CENTRONICS PARALLEL INTERFACE
4PL7005 $74.95
e MEMOTECH RS232 INTERFACE
#PL7006 $99.95

PRINTERS
e SEIKOSHA GP-100A PRINTER. The revo-
lutionary low-cost dot matrix impact printer
— Uses up to 9.5" paper.

#PL7008 $349.00
e SEIKOSHA GP-250X PRINTER. The most
intelligent programmable graphic printer —
Uses up to 9.5" paper.

#PL7009 $449.00
e PRINTER—INTERFACE CABLE.
#PL7010 $19.95

e MEMOCALC. Software on plug-in
EPROM cartridge — Spread sheet analysis
— Up to 7000 numbers (when used with

64K).
#BS200C $49.95

e MEMOASSEMBLER. Plug in assembler.
Code and edit a source program in Z80
language, and then assemble into machine
code. For writing flexible and economic
programs.

#PL7015 $49.95

e MEMOTEXT. Plug in word processing.
Brings commercial standard of text editing
to your TS 1000.

#PL7014

$49.95

ATTENTION PROGRAMMERS:
Be a part of a fast-growing corporation
Repay better royalties for your high quality software for TS1000, TS2000, TI99-4, VIC-20, BBC, DRAGON, and ORIC-1 computers.

Write or callus. Intercomputer Inc., RO. Box 90, Prudential Center, Boston, MA 02199 Tel. (617) 437-1190

aS intercomputer inc
Expands the use of your TIMEX SINCLAIR 1000

INTERCONTROLLER.:,

Makes Your Life a Little Easier

Puts your Timex Sinclair 1000 to work around the clock and
does any number of tasks for you automatically (turns on/off
your lights, motors, waters your lawn . . .) at home, office or
laboratory. Just plug INTERCONTROLLERw into your com-
puter and program each of the unit three switches individu-
ally. The INTERCONTROLLER« is software programable
time intervals from fractions of seconds to days. You can
connect up to four INTERCONTROLLER» units to your

#PL7013

computer if you have a SOFTBOX».

CARTRIDGES

Don’t Wait For Cassette Based Programs To Load

Many intercomputer programs are also available on solid
state cartridges. Just plug a cartridge directly into your TS
1000 or if you have a SOFTBOX», connect up to four car-
tridges to your computer at a time and enjoy having instant
and easy access to your favorite program.

#CS1001
FLEXIBLE RIBBON CONNECTOR

No More System Crashes

For connecting any MEMORY EXPANSION, SOFTBOX»
CARTRIDGES, and INTERCONTROLLER« to your TS1000.
This flexible connector prevents usual system crashes caused

by the RAM expansion movement.
e Gold Plated Connectors
e 6 Inches Long Flat Ribbon Cable

QSAVE
A Reliable Fast Loading System

Many thousands of satisfied customers
now have a highly reliable loading system
which operates 16 times faster than the
Sinclair system.

This is what you get:

1. A cassette interface which plugs into
your Timex 1000 to improve the sig-
nal quality. To make loading most reli-
able, an AUTOMATIC LEVEL CON-
TROL, an OVERLOAD WARNING
LIGHT, a SAVE/LOAD SWITCH, and
an ON/OFF switch are also built into
this unit.

2. Highly sophisticated software which
will load and save programs at 16
times their normal speed (i.e. 8K in 10
secs; 48K in 110 secs). It works
equally well with AUTORUN pro-
grams, BASIC or MACHINE CODE.

QSAVE will operate with ANY memory
and on ANY program length. All the above
is contained in ^K of superbly easy to use

software. #PL7001 $37.95

#PL7016

$34.95

$24.95

SOFTBOX

This modular box contains four gold plated, software select-

able connectors which can hold any combination of INTER-
CONTROLLERwn units or software CARTRIDGES. The
SOFTBOXm has a DC power input jack, an on-off switch, and

an LED indicator, providing a better alternative for powering
on/off your computer and peripherals eliminating overloading

$17.95 problems.

MCODER
Makes Machine Code Redundant

Now there is no need to spend long
tedious hours writing and debugging your
programs in laborious machine code — let
MCoder do all the hard work for you . . ..

MCoder is the first real integer compiler
for the Timex Sinclair 1000. This very
sophisticated piece of software will simply
translate basic programs into machine
code for you, giving an average speed
improvement of the order of 75 times
although in certain cases the improve-
ment can be as much as 900 times faster.

MCODER IS DESIGNED TO BE AS
SIMPLE AS POSSIBLE TO USE....
1. Load MCoder
2. Write or load your basic program as
normal
3. RUN and debug your basic program
4. Compile your program using a single
PRINT USR command. If you have
made a mistake MCoder will tell you
exactly where, allowing you to correct
it before it is too late.

As an additional feature basic programs
can be compiled and "Stacked" above
each other in memory — giving you true
flexibility in your programming.

#PT4001 $18.95

STOPPER

No doubt you have felt the frustration of
not being able to see the listing or to
make backup copies of machine code

For more information on these products and our FULL LINE OF SOFTWARE

please call or write to INTERCOMPUTER.

COMING SOON: A full line of Software and Peripherals for ZX SPECTRUM/
TIMEX SINCLAIR 2000

#PL7012 $59.95

programs. Intercomputer STOPPER ends
this frustration and enables you to break
through any machine code software you
want, list the program on the screen, save
it on another tape, or print it if you have a
printer. Simply load STOPPER and your
program into your TS 1000 and follow
instructions. Once loaded STOPPER stays
in your computer and you may use it for

other programs. #PT4002 $18.95

DEALERS/DISTRIBUTORS PACKAGE
AVAILABLE.
Phone orders: (617) 437-1190 7 days a week.

[wai to: Intercomputer, Inc., P.O. Box 90 ne
Prudential Center, Boston, MA 02199
Tel: (617) 437-1190

Telex: 951141COFAR

PART # | QTY. | UNIT U.S. $| TOTAL

Shipping and Handling 4.95
Mass. Residents Tax 5%
O Check Total
O Mastercard
O Visa
Account No. Exp
Name
Address |
City State Zip i

"Directory of Suppliers" for the address.
Note that the prices do not include state
sales taxes where these are applicable and
not all entries were clear as to whether the
price included shipping.

We want to emphasize again that the
Buyer's Guide is not a catalog, and we
cannot guarantee the accuracy, complete-
ness, or timeliness of the information. This
is especially the case with prices because
they are very changeable in such a com-
petitive market. Check the supplier's cur-
rent ads for up-to-date prices and full

ordering information before making a de-
cision or placing an order. If there is no

ad, check with the supplier for full details
before ordering.

The TS2040 Printer and ROM Bugs

ZX Users Group of New York

Now that the Timex printer has made
its appearance, Sinclair and Timex owners
across USA will be adding LPRINT state-

ZX users Group of New York, Box 560, Wall St.,
New York, NY 10005.

E [S YOUR :
SINCLAIR WORKING HARD,
OR HARDLY WORKING?

If you've been looking for a better way to keep your
Sinclair busy, the search ends with Graphicomp.

We've selected more than 60 unique software
packages designed specifically for the ZX-81/TS1000.
Choose from the largest variety of IK to 16K soft-
ware available for education, programming,
testing, and of course, the popular challenges
and games. Write us for the name of the
Graphicomp dealer nearest you.

Dealer enquiries welcome.

GRAPHICOMP

U.S. order to:

55 York Street, Suite 100, Toronto, Ontario M5J 1R7
It's time your Sinclair got to work.

ments to their favorite programs. They
will soon find out that there are some bugs
in the LPRINT Command. The problem is
not in the printer, but in the Sinclair 8K
ROM.

The first bug involves the improper
printing of numbers between .01 and
.00001. The program below, and the out-
put following it, illustrates this.

10 LET N=.00001
20 LPRINT N
30 LPRINT .00001 .
40 LPRINT STRS .00001
50 LET N$=STR$ N
60 LPRINT N$
OXYZ1
OXY Z1
OXY Z1
00001

As you can see, lines 20 and 40 do not
print .00001 correctly. The May 1983 issue
of Syntax describes this ROM error along
with a hardware fix by putting a modified
Sinclair ROM on EPROM.

For those of us who do not have access
to an EPROM programmer it is necessary
to program around the bug. Lines 50 and
60 above show how.

Whenever you LPRINT a number which
may be in the range of .01 to .00001, you
should first assign it to a string using the
STR$ function. Then LPRINT the string.
Notice that using STR$ in the LPRINT
statement does not correct the problem.

Our ZX Users Group of New York has
found some additional bugs. STR$ some-
times does not work right with other string
functions in LPRINT statements. For ex-
ample, the following five LPRINT Com-
mands do not give the expected results, or
give error messages when they should not:

LPRINT (STR$ 100)(2)
Gives: 100 (should be 0; also stops with
error code 3).
LPRINT LEN STR$ 10
Gives: 100 (should be 2).
LPRINT STR$ 100 AND 0
Gives: 100 (should be blank line).
LPRINT VAL STR$ 100
Gives: 100 (correct, but then stops with
error C).
LPRINT CODE STR$ 100
Gives: 100 (should be 29).

The moral of all this is, if something you
try to do with LPRINT does not seem to
work right, put the expression into a string
and LPRINT the string.

We hope that Timex or Sinclair will
offer upgraded ROMs to correct these

bugs. EL

July/August 1983 © SYNC

teru EAs

8K ROM
Type in the following lines:

1 REM 12343

50 PRINT “###”;

Type in the following lines: 60 GOTO 20

ES Done 15514,62 5 PRINT “ (32 inverse spaces) ” Press RUN and ENTER; press CONT
ZB Pore 18B15/51. 10 PRINT AT 20, RND*30;*." and ENTER for another screen.

6517.71
50 POKE 16513,2801

b 20 SCROLL
nO? PRINT AT 11,9; 30 RUN

Line notes:
20: 5 letters.

$e POKE Eu Press RUN and ENTER. 30: A random letter A-Z.
100 coro Graphics notes: 50: 3 spaces after each word (8 * 4 — 32

Put the computer in SLOW mode. Press
RUN and ENTER. After the program is
run once, you can remove lines 10, 30, 40,
and 50 and change line 100 to GOTO 20.

Graphics notes:

60: Inverse "SYNC MAGAZINE". Any

— a full line).

Author's comment: This is the first Basic
program I wrote. It is a simple one to
produce a screen full of 5 letter ^words"
made up of letters picked at random. I ran
the program and then stared at it and the

5: 32 inverse spaces.
10: Inverse period.
Our thanks to:
Scott Brodsky
71 Totman Rd.
Lowell, MA 01854

message can be put here, but use the
inverse for best effect.
Our thanks to:
Raymond Marasa

Type in the following lines:
20 FOR N-1 TO 5

screen for a long time. Then I decided to
send by ZX81 back to be fixed. Then I
stared at the screen some more...

Our thanks to:

652 Aspen St. 30 PRINT CHR$ (36+INT (RND*26+ Eric Chandler
Coquitlam, B.C. .5)); 228 Arlington St.
Canada V3J 3W2 40 NEXT N Lynchburg, VA 24503 a"
SOFTWARE
DR.FLOYD™ ZX81- TIMEX-SINCLAIR 1000. ÇIN 76

Psychoanalysis by computer? - well not quite
but Dr. Floyd will carry on a conversation
with you using psychoanalytic techniques
giving the appearance of artificial
intelligence. Requires 16K RAM. $10.00

GRAPHICS PAC I

An introduction to Sinclair graphics -
includes: 2 random picture drawers, allow
creation of "Pop" art. A screen formatter
which allows placing any character
anywhere on the screen. Complex pictures
may be created & saved. Doodler allows line
art drawings to be created & saved.
Hequires 16K. $10.00

PLAY"

GUN

Includes Jargon -a jargon word generator.
"Animal" - a fun game where the player
teaches the computer all about animals.
"Story" - the computer writes stories using
the players input names, places, etc. Can be
Ivery funny for kids, "Haiku" - the computer
composes HAIKU like poetry. Requires 16K.
$10.00 Ux

SPECIAL! Order all 3 programs

for only $25.00!!

DE inim rue nc ji 5
eae
fe iu mu um

HAKU

These are the BEST BUYS cause loss of programs due to poor

DR. FLOY! Da
$3500 Shipping
included

A
- SIN 16
ons 16K Byte RAM |
a d
E. :

This attractive memory expansion allows
you to run virtually all the programs written
for the ZX-81 or Times-Sinclair 1000. SIN16
IS fully compatible with other plug-ins and is
superior to other RAMs because it uses 3096
less power. This extends the product life to
many years. We use the best gold- plated
connector on the market, so SIN16 will not

in this magazine

ORDER TODAY!!

connection to the computer. Get real power
for your computer.

Send check or Money Order ORDER A SIN16 TODAY!
All shipping included SPECIAL! - Order a SIN16 and get any one
Calif. residents add 6% tax. of the 3 programs FREE!

Phone orders: CALL
805/482-3604 24 hrs.

_ Just list the one you want. _
10 day return privilege on all hardware -

6 month parts and labor warranty.

This is a TRUE BARGAIN! DON'T MISS IT! Eo. credit card orders, include all Extended service always available -

All software is on high quality cassettes and
is replacement guaranteed.

July/August 1983 9 SYN

PROPOS TECHNOLOG

information on card.
DEALER INQUIRIES WELCOME WE SERVICE WHAT WE SELL.

350 N. Lantana Ave., Suite 821 e Camarillo, CA 93010
11

INPUT, OUTPUT, and Other Confusing Things

In this issue Perceptions will take up
I/O (Input/Output) ports. The funda-
mental issues are discussed, and a sample
method for their application to the
TS1000/Z X81 is described.

Introduction

I sit in front of a video terminal. A
cursor flashes in a corner of the screen. I
press the key labeled ENTER on my com-
puter. From behind, I hear a ‘ka-chunk’ -
the familiar taka-taka-taka of my main
printer.

Soon a message appears on the screen.
It reads: ‘PRINTING COMPLETE. O.K.
TO CONTINUE?” I activate the tired
muscles in my arm, reach to the keyboard
and, extending my index finger, press the
Y key. The red LED on one of my disk
drives begins to flash!once, twice, and
again. Soon they glow constantly.

Then, to my great surprise, the speech
section of my computer wakes from its
day-old sleep, and begins to recite the
alphabet. Next each light in the room
begins to cycle: first off, then on, then
off, and then back to its original state.
The television in the next room goes on,
and I hear gunshots from the western
movie. I decide to sit back, smoke a
cigarette, and go quietly out of my mind
contemplating the reason for my com-
puter’s apparent loss of its mental
faculties.

Contemplation, as usual, leads me no-
where. Pressing, repeatedly, the RESET
button seems to have little or no effect on
its trip into never-never land. I pull the
plug.

The above scenario may sound like an
excerpt from HAL's adventures in 2001,
but it is not. It is a scene that occurred in
my study a few nights ago. Such an occur-
rence is, admittedly, a rare occurrence in
my house. It is, however, more likely to

occur in my house than in the average
house in, say, a less technically-oriented
environment. It usually comes about
during the testing of some new feature
that I am adding to my computer. Often
an I/O port. I scramble a few wires, plug
in a board upside — down, or backwards,
— whatever.

This time, however, the event was un-
precedented: I had a witness. Someone
would, finally, be there to back me up
when I told my friends what had
happened.

My friend (or should I say savior?), a
novice in the computer field, was amazed.
“What is happening?" and “Can I help?"
seemed to the most frequent comments.
Once I had cleared up the mystery in my
head (a solder bridge), we went to the
local coffehouse and discussed music,
good coffees, and the events of the
evening.

Not surprisingly, the evening's events
dominated the conversation. What had
happened, he wanted to know. What
ensued was an explanation of I/O. Input/
Output: those operations which concern
the computer's communication, and inter-
action with the outside world. Soon the
cafe closed, and we returned home. The
discussion continued, and continued, and
continued... Upon reflection the next
day, it occurred to me that the material
that we discussed would make a good
article. What follows is just that: a sum-
mary of that discussion.

What Is an I/O Port?

My friend, having heard me use the
term dozens of times that night in conver-
sations with myself, asked me: "What is
an I/O port?" An I/O port is a channel,
through which, a computer "talks" to the
outside world. When a computer wants a
printer to print a particular character, it

perceptions David Ornstein

sends, via an I/O port, the code that
represents the desired character to the
printer. The printer then decodes the
charater into the proper internal format
(i.e., dots), and eventually yields a char-
acter on a piece of paper.

More properly, the computer sends the
character that it wants printed to the
printer via an output port connected to
the computer. Hopefully, a sane printer is
listening to the output of that output port.
The printer will notice that the computer
has sent a character to it, and it will read
that character through its internal input
port.

Noticing the questioning look on my
friend's face, I ordered two more cups of
coffee, and dove head on into a detailed
description of I/O ports.

Types of Ports

There are two kinds of I/O ports: paral-
lel and serial. Parallel ports are the easiest
to understand, so I will tell you about
them first.

A parallel port transfers data, usually,
eight bits at a time. Eight bits, as you
know, comprise a byte—the basic chunk
of data in a microcomputer. Larger com-
puters, using parallel ports, may transfer
as many as 22 bits in a shot. It depends on
how the processor is organized. The
Timex/Sinclair 1000 uses an eight-bit
microprocessor, the Z80. The Z80 has an
eight bit data-bus. A data bus is, concept-
ually, a series of wires (i.e., eight) that
carry around data. The Z80, having eight
of these “wires,” will use an eight bit I/O
port. I reached for an "engineer's best
friend" — the napkin.

*Let me illustrate," I said. I drew a box
with eight lines coming out of each side.
One line extended from the top. This is a
simple I/O port. (See Figure 1.)

Eight LEDs (Light Emitting Diodes) are

July/August 1983 © SYNC

HE ZEBRA KEYBOARD

Why is it the best?

SHARP
2-COLOR
LEGENDS

SPACE-BAR

FULL-TRAVEL
GOLD-CONTACT
KEY MECHANISM

FOR ZX81
& TS1000

$89.95

ORDER C141

ONE-YEAR
LIMITED
WARRANTY

Now Timex Sinclair users can enjoy many of
the benefits IBM and all the biggies are getting
with Green Phosphour monitors ... and at a
fraction of the cost.

e The Green Screen is a specially molded
plastic optical filter which relieves eye strain
by enhancing character contrast and by elim-
inating the components of white light which
cause eye fatigue.

e The Green Screen fits right onto the picture
tube like a skin because it is molded to
match the curvature of your TV. We also in-
clude some invisible reusable tape for secure
fastening.

e The filter material that we use is just right,
not too dark nor too light. The result is a
really eye pleasing display.

e The Green Screen will fit any 12" TV or
monitor and can easily be trimmed with a pair
of scissors to fit any smaller size.

Order C140

rhe Timex Sinclair Printer for your Timex Sinclair 1000

or Sinclair ZX81 prints 32 colums wide, two lines per second, with full

CONNECTOR FOR
OPTIONAL NUMERIC
KEYPAD

21 - Superior Quality: Same key mechanism as used
by IBM, Texas Instruments, Hewlet Packard, and

others. Full travel, gold inlaid contacts for over 10
million operations.

a2 - Professional Full Size Layout: 40 keys corre-
sponding one to one with your computer's, plus

space bar in case you do word processing.

23 - Looks Good & Feels Good: Attractive custom
molded enclosure matches your system. Sharp
TS1000 legends in two colors are easy to read and
will never wear off.

#4 - Easy Installation: No soldering or technical
knowledge required. Done in minutes with simple

instructions.

ATTRACTIVE
ANGLED
ENCLOSURE

YOU DECIDE

Order yours today. (Call Toll-Free.) If you are not

delighted with your Zebra keyboard and the way it

15 DAY MONEY BACK
GUARANTEE ON ALL
ZEBRA HARDWARE

Experience for yourself how much the Key-
board Beeper improves the use of your
TIMEX keyboard. Simply plug it into your
computer's expansion connector and hear a
beep whenever a character is accepted by
the computer's keyboard input routine. No
software is required. Features expansion
connector for RAM etc.

BONUS 1 - You can trigger the beep from
Basic. Great for program prompts, timers,

BONUS 2 - A beep every 9 minutes will
remind you that your computer is on.
ORDER #C133..... ess. $19.95

graphics and text capability. The TS2040 prints silently in two modes: 1)

full-screen printing with single-key copy command, and 2) program-

controlled printing allowing for custom control of the printing format. The

TS2040 connects easily to your computer, has simple ON/OFF controls,
comes with one roll of paper, easy to understand instructions and a 90-day

Order Zebra Cat. #C144 $84.95

limited warranty.

Printer Paper

EE Tech info & NY State call
(212) 296-2385 9-5 EST

THERMAL PAPER FOR THE TS2040
SIX ROLL PACK #C143 ..

$11.90

transforms your computer, simply return it within
15 days for a prompt and courteous refund,
(including shipping and handling).

Turn printer on

o
-<
Z.
ur
m g
m
A
N
m
JJ

Voltage is 7+?
*UNLIMITED VOCABULARY.
*BUILT IN AMPLIFIER WILL DRIVE ANY

SMALL SPEAKER OR YOUR STEREO.
*PLUGS INTO REAR CONNECTOR ON
YOUR TS-1000 OR ZX-81.
* BUILT IN VOLUME CONTROL.
*FEATURES EXPANSION CONNECTOR
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*COMES COMPLETE WITH USERS MANUAL
AND SOFTWARE CASSETTE.

ORDER C141 $79.95
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FOR ZX81
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5 B C.0.D. ADD $3.00 EXTRA.

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arranged so as to light when their corres-
ponding control lines are activated. To
make them all light, the computer must
activate all the control lines. It does this
by sending an FFh (1111b) to the output
port. To turn on LED 2, LED 5, and LED
6, the computer must send a 00110010b.

To send data the computer must place
the desired data on its data bus, and
activate the STROBE line on the output
port. Activation of the strobe line says, in
effect, to the output port: "Take what
I'm giving you on the data bus. Put it on
your output lines, and keep it there — even
if I go away. Don't change it until I tell
you to (i.e., activate the STROBE line
again)." This effect is known as latching.
The device (an integrated circuit, prob-
ably) that performs the action of latching
is known as a latch. When one piece of
data is latched, it stays on the output of
the latch—until something new is
latched.

Address, Control and Data

When the computer wishes to read data
from a keyboard, or read data from a
cassette tape recorder, or send characters
to a printer, it must know how to tell all
those devices (i.e., I/O ports) which one
is being talked to. In the case of an aver-
age computer, there may be as many asa
dozen— or more —output ports. How does

. LET YOUR COMPUTER RUN NAKED!

(+16K) with action games,

Computer-
E Wear Software dresses up your ZX81/TS 1000
innovative (fun)
learning aids and profit- boosting business

Figure 1.

STROBE

it (the computer) know which STROBE
line to activate. how does it “activate”
them, for that matter?

Let me try to explain by way of an old
analogy. Imagine, that the printer to
which a character is to be sent lives on a
road, He—Mr. Printer, that is—has a mail-
box. If he has a mailbox, then he has an
address. When Mr. Printer’s friend the
computer wants to send a message
(output) to Mr. Printer, he gives that
message to Mr. Mailman (the Data Bus).
Mr. Mailman carries the message to Mr.

Printer’s mailbox (Output Port.) Mr. Mail-
man then puts it into the mailbox, and
strobes it (i.e., he raises the “mail-here”
flag). Actually, the mailbox combines
both the output port of the computer and
the input port of the printer.

When Mr. Printer is ready to read his
mail, he goes to his mailbox. He removes
the message, and reads (processes/ prints)
it. He also signals to Mr. Computer that
he is ready to receive more mail by lower-
ing the “mail-here” flag. This is a common
feature of I/O port arrangements. It says

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but with 1 difference -- your computer
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THESE ARE QUALITY KEYBOARDS SPECIFICALLY
DESIGNED FOR SINCLAIR/TIMEX COMPUTERS AND
OFFERED ONLY IN KIT FORM TO SAVE YOU ASSEMBLY
COSTS. USE OF ACTIVE CMOS CIRCUITRY PROVIDES
LOW POWER REQUIREMENTS (ABOUT 1mw) AND
ALLOWS THE KEYBOARD TO BE POWERED DIRECTLY
FROM THE ZX81 AND TIMEX 1000 POWER SUPPLIES.
MORE IMPORTANTLY, SINGLE KEYSTROKE ENTRIES
(NO SHIFT REQUIRED) ARE ENABLED FOR 80% OF THE
KEYS THAT MUST BE MANUALLY SHIFTED ON THE
ZX81, TIMEX 1000, AND MOST OTHER KEYBOARDS
THAT ARE CURRENTLY AVAILABLE.

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INCLUDE $4.00 SHIPPING & HANDLING

CALIFORNIA RESIDENTS ADD 6% SALES TAX

July/August 1983 © SYNC

ZEBRA JOYSTICK ADAPTOR

Allows you to connect any Atari compatible joystick to your ZX81 or TS1000. |

CONNECTOR FOR 6 JOYSTICK GAMES $9.95
RNC EIC: ATARI JOYSTICK $6.50

ADAPTOR $19.95
SIMPLY

PLUG IT The ZEBRA Joystick Adaptor comes
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C102 BYTING DEEPER INTO YOUR TS1000 $12.95
C103 NOT JUST 30 PROGRAMS FOR THE ZX81 .. $ 9.95
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DEALER DISCOUNTS AVAILABLE.

to the sending device, that the receiving
device is ready to accept more data.
When the data is sent to the I/O port, the
DATA AVAILABLE flag is set. (This
was the “mail-here” flag in the above
example.) This interaction between out-
put device, and input device is called
handshaking.

Without proper handshaking, at least
two fatal occurrences are possible. First
is the case where the output device is
sending data faster than the input device
can read and process it. An extreme

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Addition of new functions in your ZX81/TS1000 to increase
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example might be the case in which a
computer is sending characters at a rate
of 150,000 cps (characters per second).
An average printer can read characters
at a rate of approximately 150 characters
per second. Every second, the printer
would miss 149,850 characters— clearly
an unacceptable number. Handshaking
solves this problem. The computer reads
the DATA AVAILABLE flag that it set
(i.e., turned on). It waits until the printer
has reset the line before sending another
character.

FOR ZX81/TS1000

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Price — $10.00

This new arcade -
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Please add $2 to each order

The other problem arises when the
computer is reading data from a device
that is presenting data slower than the
microcomputer is reading. A keyboard is
such a device, and a keyboard is a com-
monly used device indeed. The keyboard
has an output port, in this example. When
the user presses the W key, the output
latch grabs the code for a W, and holds it
on its output.

Meanwhile the keyboard is being read
by the computer 50,000 times per second.
How many times, in that second, do you
think the computer will read the key W.
Clearly, the synchronization provided by
handshaking is critical.

Returning to the issue at hand, a typical
microprocessor, such as the Z80, has an
eight bit data bus, a 16 bit address bus,
and a collection of control lines. These
control lines indicate the conditions of
the data bus, and the address bus. They
dictate, for example, that the 16 bit num-
ber on the address bus is the address of a
memory location, and that the data on
the data bus should be written into that
memory location. They might specify that
the address on the address bus is currently
specifying a particular input port, and
that the designated port should place its
data on the data bus for the Z80 to read
into one of its internal registers.

The address bus, being 16-bit wide. can
specify any of 65536 addresses
(65536—2**16). The number 65536 is
often referred to as 64K. One “K” is 1024
(2**10). The 64K addressing area (address
space) of a computer is usually filed with
various items: RAM, ROM, and I/O
ports. The Timex/ Sinclair 1000's memory
space is shown in block form in Figure 2.

Figure 2.

In the next issue, I will continue dis-
cussing I/O ports. I will describe a way to
open up some of the apparently filled
address space of the Timex/Sinclair
1000.

Until next time, same relativistic time
period, same non-Euclidian universe.

July/August 1983 © SYNC

FLOPPY DIS

INTERFACE

Available either completely assembled, ready
to just plug-in or in an easy-to-assemble kit
with the following features:

e Interfaces with your Shugart SA 400 or
any equivalent 35 or 40 track drive system
(please specify when ordering) e Loads 16k
program reliably in seconds e Compatible
with all RAM expansions e Direct plug-in to
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2/32 ROM e DOS commands from direct
mode or from your BASIC program.

e DOS commands:

INIT DSAVE DLOAD DIR . STAT
CREATE WRITE READ KILL NEWD

A Name You Can Depend On

Sinclair ZX81 or Timex 1000

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Robotics on a Budget Bruce C. Taylor

The Project

A little over a year ago I decided to
start building a robot. I had no idea that it
would lead to a project fully controlled
by a computer. However, as I started
reading more about robots and the ro-
botics law, I realized that a true robot
had to be a self-contained entity able to
operate as independently as possible. At
that time I did not even know what a
ZX81 was, but, after a few months into
the robot project, I bought my first ZX81
computer (the family now owns two).
Even then I did not immediately realize
the possibilities of ZX81 control. About
three months later after reading about
the expansion possibilities of the ZX81, I
decided to try to combine the ZX81 with
the robot.

If you are not interested in such a large
computer control project, the hardware,
software, and interface methods de-
scribed here can easily be applied to a
smaller project such as a robot arm.

The Robot

I will not describe the actual construct-
ion of the robot in any detail. The design
for the robot was based on the Radio-
Electronics magazine reprint series of
articles titled, “Build this robot for under
$400."

Although my project robot has many
similarities to the RE Unicorn-1 robot, it
also has many differences. As complete
as the series of articles was, there were
many errors and incomplete explanations
of the design.

The basic improvements on the phy-
sical design are as follows. The diameter
of the body was reduced to sixteen inches.
It was obvious that a body any wider,
with arms added, would have trouble
navigating through household doorways

and other tight spots. The drive wheels
were placed in the front to pull the robot
around and aid in traction. This moved
the battery to the rear and aided stability.
The base was made the same diameter as
the body for aesthetic reasons. Although
small access doors were located in both
the front and back of the base, the re-
quired access to the base was achieved
by making the entire base plate of the
upper body, with turntable, hinge back-
ward to allow full access to the inside of

the base. And finally, the computer with
expansion board was located on the top
and underside of the hinged lid.

To save money and learn as much
about the input/output circuitry as pos-
sible I purchased the Computer Con-
tinuum expansion board and the Zodex
RX-81 input/output boards in the bare
board form and built them up from com-
ponents purchased separately. I built up
all the other boards and even etched some
myself.

Figure 1. Power Supply.

FC1
W C3
12V v
in} auos

C2 out

IC1 LM350, 3 Amp adjustable power regulator
D1,D2 1N4002

R1 120 Ohm, 1/4 watt

R2 5K Ohm adjustable pot (10 turn)

C1 .1 MFD, 25V

Cz 1 MFD, 15 V

C3 2300 MFD, 33VDC, 50V surge

FC1,FC2 125 uH, 3.5 Amp hash filter choke

Note: Heat sink IC1 well (3 to 4 Sq inches)

July/August 1983 © SYNC

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power supply

Photo 1. Looking through the dome.
Dome removed show
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Photo 4. 5 volt DPDT relay board

Photo 3.

July/August 1983 ° SYNC

3fY IVA dOL = SADIdd LS3NOH + ALITVNO 1S38

3fY1VA dOL = SADIYd LSANOH + ALITVND 1S38

KVC, INC. INDIANAPOLIS,
ox sc, THE WINNING

" sticks with the ZX-81

jan i games. Work instructions
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MEMORY
EXPANSIONS

Highest Technology and
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add-ons and LED indi-
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16 K = $54
32 K = $95
64 K = $135

QS SOUND GENERATOR

Integrating the AY-3-8910 chip with 16 internal records. 3
independent tone generators. Scale of 5 octaves. Led to
inform when the generator is working. Volume potenti-
ometer and amplifier output. |. $49

RIBBON CONNECTOR

Extends the ZX-81 BUS to avoid
failures in the memory and peri-
pheric connection. $19

CENTRONICS INTERFACE

Interface to connect the ZX-81 to a serial printer
which can work under this norm. .. $69

PRINTER CABLE $16

INTERFACE FLOPPY DISK (SUGAR)

Based on standard unit of 5% with controller
interface. It has 43 K bytes of storing. Possibility
of working with file. Programs loading in less
than 20 seconds. $115

QS
PROGRAMMABLE
CHARACTER
GENERATOR

Allows to program 128
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It has 1 K RAM to store
them. Switch ON/OFF
to select new charac-
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PROFESSIONAL KEYBOARD

52 keys - Fully assembled - No soldering - Outlets for MIC. EAR.
TV, etc. $89

CROAKA
CRAWLA

CROAKA CRAWLA

$12
Author: John Field

It’s not easy being a frog what
with the trucks and lods, the cro-
codiles and turtles. The continual
battle for survival, struggle with
the universe ... Us frogs do some-
times get a little carried away,
see you on the far bank.

Special Features: Flies, croco-
diles, Sinking turtles, Inverted
logs, Progressive difficulty attack
waves.

GALAXIANS
& GLOOPS

Pts.

GALAXIANS & GLOOPS

Author: T. Beckwith

The peaceful Fragnn battle the
large Wobbly Galaxian birds with
a device built of dragon gut and
with small furry bombs, 'Splach,
Ploof,Splach, Ploof, Tank, Ploof ...
A keen eye and a fast hand help.
Special Features: Two types of
swooping, bombing, galaxian, All
fully adjustable.

GLOOPS;An amazing maze ga

$16

SUBSPACE STRIKER

It comes from out of nowhere and
then vanishes back into the ether.
With your deadly antimat torpe-
does, you unleash havoc in the
Federation's Spacelanes.

Plus Zor battle of the robots.

$12

SUBSPACE
STRIKER

SOFTWARE - Quicksilva s
latest bits make your ZX81/TIMEX

1000 give you the best in exciting
entertainment and fun.

PIONEER TRAIL: — S12

Author: Marion Stubbs

A Western adventure Featuring
20 levels of play..'Mind Game’
plus shooting rifle-speed uses all
keys and is measured against the
players personal average respon-
se. This game is based on histo-
rical data.

MUNCHESS

PIONEER

MUNCHESS $12
Author: A. Laird

Beware the Munchees, a board
creaks in the time lost corridors.
A ghostly presence, a rush of
wind, a forgotten echo whispering
around the house and following
chuckle of ghosts rolling forward
on cold breezes ...

Special Features: Ghostly ghosts,
pills and fruit, munchy munchees.

TRADER

A trilogy of 16 K programs that combine to give an epic 48K
graphic adventure. As a galactic trader, you deal with some very
bizarre customers indeed. Will you live to tell the tale?

It is hard enough to look at an amorphus hydrosilicon blob from
Psi, never mind swing a deal with one. But when they ask to pick
your brains, do you really know what they have in mind ...?

As an intergalactic door to door salesman, you do the rounds of
the Moons od Meridien, a beautiful gas giant in the Altair system
some 16 light years from Earth. The life is tough. the bargaining
hard. You can gain fame and fortune or end up spaced out in a
Deltan hellhole.

You deal in Synthomunch and Boosterspice, Petrochem and
Gold. You meet other ex-Terrans and unimaginable alien creatu-
res. You go gravity diving in your little spacehooper 'Pegasus'
and have to land on a solid chunk of Uranium to pick up fuel.

$14

3Qn1VA dOL = S3O2IHd LS3NOH + ALITWND 1S38 —

a
engmy craft ... PF "ais
Seca Feature >

QS SCRAMBLE

Author: Dave Edwards

A landscape of mougkiri
teaus and vallies stid
ship as waves of ali
firing from above a

up from the. ground. F

explode below as yous

EIEII FX Fx FX IN FX FX IN rS

e KARTES VIDEO COMMUNICATIONS, INC.
K COMPUTERS & PERIPHERALS DIV.
10 EAST 106 th. INDIANAPOLIS.

PLEASE SEND YOUR ORDER TO:

MAIL: KARTES VIDEO COMMUNICATIONS, INC., DIV.
COMPUTERS & PERIPHERALS
10 EAST 106 th. INDIANAPOLIS, INDIANA 46280

PHONE: 800-428-6163 (except in Alaska and Hawaii)

800-692-6048 (in Indiana)

A yoona

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— JYew ww AAA
[AMERICAN EXPRESS

y O VISA
M 0 MASTERCARD
[] CHEQUE/P.O. NAME

= ADDRESS
CALL TODAY TOLL FREE

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INDIANA. 46280

4 EY | ITEM PRICE TOTAL

ANTVA dOL = S39lldd LS3NOH + ALITVNOD 1938

G s i7 "Bs B

e'll keep
. your Sinclair summing!

EP CP CP CE GE CES Om UR CR CR
"rs 6S 68 6 CS CES FR. oe Oe En
co Pm Cm CH CER CH CU CUR UR a

OUR $1

WILL SAVE YOU MONEY.

Timex too!

Typical repair charges for a
Sinclair ZX81 can run from $25 or
$50 up to the replacement cost of
the unit. So why take chances?
MicroSync will guarantee unlimited
service for one year, parts included,
at one low price. With return postage
and handling paid. Plus our VIP
treatment for fast turnaround.

MicroSync’s experienced
technicians are ready to service
your ZX81 or Timex/Sinclair 1000
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MicroSync is THE Sinclair
authorized Service Center.

We made over 10,000
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Your Sinclair computer is a
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The fine print. MicroSync’s Maintenance Agreement covers all parts and service for 12 months
after the expiration of original warranty. For units over 90 days old, coverage is for 12 months
from the date of the Maintenance Agreement. Kits or modified units may require a surcharge.
MicroSync may not repair units damaged by abuse or negligence. Liability extends to repair or
replacement only.

SINCLAIR ; AND TIMEX OWNER: RPROTECTION SERVICE PLAN

We have the experience it takes.
We have the parts on hand.

So act now! If your unit is less
than 90 days old you can purchase
our Owner-Protection Service Plan
for only $145

D wai To: MicroSync

162 Marlboro St i
Keene NH 03431
l Please send Maintenance Agreements for Í
j the equipment listed below: f
i ZX81 or Timex/Sinclair 1000 j
Less than 90 days old
i (include proof of purchase) ........ $10.00 ea. i
Over 90 days old. uu. S, $29.95 ea.
|] 46K RAM i
B Less than 90 days old f
(include proof of purchase) ........ $10.00 ea.
j Over 90 days old- — X. rss $29.95 ea. B
i Total Enclosed.......... U.S. $ i
j Serial nos. B
: C] check O MiC Ll] VISA 1
i Card # Exp. |
É Name 1
Address i
City State Zip -J
L 2. M^ M. . M a . 1M MHM HM 3|

MicroSync

AUTHORIZED SINCLAIR SERVICE

The Power Supply

The biggest problem on the electronic
side resulted from choosing to run every-
thing from a single 12 volt battery. The
DC motors and the controlling relays
caused problems because the voltage and
amperage (frequency) spikes which they
generate wreak havoc on the computer.
The single battery, originally a large

from Jameco, and the hash chokes were
ordered from Mouser. The power supply
works so well on my wall-powered ZX81
that all problems previously attributed to
LOADing and SAVEing glitches have all
disappeared. Also, with the large can

Figure 2. Relay Functions.

motorcycle battery since replaced with a BEY Fmc fom Moton Drive)
small car battery, simplified the power 1 Upper body rotate left
management problem. 2 Upper body rotate right

The final solution to the spike problem 3 Left drive wheel forward
had an added benefit for the ZX81 used 4 . Leftdrive wheel reverse
as the home computer. If you have never 5 Right drive wheel forward
tried to use a small computer in Europe, 6 Right drive wheel reverse
with the “spikey mains” as the British 7 (not used)
refer to their noisy wall power, you cannot 8 (not used)

9 Left shoulder down

dream of how many ways a computer can
bomb. The problem is the same here in
West Germany where I am currently
living.

The power supply (Figure 1) solved all
spike problems. For the robot, the 12
volts in comes from the battery. For a
home computer application, the 12 volts
in would come from a rectified 12 volt
transformer output.

The key to the success of the design is.

the large can-type capacitor (C3) and the
hash chokes. The capacitor is available

Trans
RX-81 Output switch

RLY DO-7 wire color PC conn Base Coll Coil
(in) (out) (in)

i 1*9 blu/sht 10 L. 10 3
E 1-6 wht/blu 11 M 11 M
E: El wht /grn 6 F 6 P
4 lc grn/wht 7 H 7 H
ra Lie wht /gry | a J a d
ó 1-4 gry/wht a D 4 D
Z wt) X nf) X
a cand Y KA Y
9 gel wht/grn 12 N oes N
10 e qicnZwht Lo E 1.3 E
11 Ade wht /ory 14 R 14 R
P 2-4 gry /wht 12 S 13 3
l3 Ph £ xe Z
14 o E a a
LS Fie blu/wht 16 X 16 T
14 Feeds| wht /plu Lf Lu I7 \J
I eg arg/wht 18 V 18 V
18 ct wht /arg lw bj t? ud
19 i7 arg/wht 9 E. 9 E
Eu 1-8 wht f/org at s x D

Gnd Blu = ak

+5 volts

RX-81 output board #1 wired as “out 7”.

10 Left shoulder up
11 Right shoulder down
12 Right shoulder up
13 (not used)

14 (not used)

15 Left elbow down
16 Left elbow up

17 Right elbow up

18 Right elbow down
19 Right hand close
20 Right hand open

Figure 3. RX-81 Output.

emitters)

relays

RX-81 output bo

capacitor, the house lights can moment-
arily dim with no effect on the computer.

The Control Relays

The heart of the robot control is the 5
volt double pole double throw relays
driven by the computer output which in
turn activate the 12 volt robot motors
and solenoids. The functions of these
relays are listed in Figure 2. Although
only sixteen are used, the 44 finger circuit
boards used are capable of handling up to
twenty relays. In my design these relays
are double buffered from the computer
output drive with both transistor switches
and small DIP relays. The 12 volt relays
(5 volt coils) are wired similar to the RE
reprint layout with some important dif-
ferences which will be explained later.
Figure 3 gives a complete wiring table
from the RX-81 output through the 12
volt connections to each motor/solenoid.

I will now quickly walk you through
Figure 3 describing the control of relay
#1 and then explain each component in
more detail.

Relay #1 is controlled by the output of
D4 from one of the RX-81 input/output
boards. D4 is designated as 1-5 meaning
that it is the fifth of eight parallel outputs
on the first RX-81 output board. It is

DIP 5v
relays
Contact Coil Contact
(out) (in) (out)
10 2) W
1i LX V
6 Roddd
i4 LUTZ
a ó D
a A e
=) d
Pus lo
n N 5
lo EK L4
14 yi =
1 pe E
gt I7
4 F
14 M Lu
17 a T
ig wd J
15 1 H
Es PG Ix
i 4 [10
e

ard #2 wired as “out 6”.

Example: Output DO from board wired as “out 7” is listed above as 1-1.

July/August 1983 9 SYNC

Cassette Software for the ZX81
and the Timex/Sinclair 1000

TEXT & PRODIR

TEXT - A program for easy editing, storage
and display. Recall pages of reports, letters,
etc. without splitting words at the end of a
line. PRODIR - A programmed directory to
organize programs and ease loading.
PRODIR can provide a table of contents for
reports or chapters contained on tape. Use
TEXT & PRODIR with your printer.

$10 16K cassette

TEXTII

The only program you'll need to compose,
edit and save pages of text. Pages are recalled
without splitting words. For Speed the
program now utilizes machine code. Includes
PRODIR. TEXTII has a variable no. of
characters per line to accommodate your
printer. Includes a string search routine, a
line renumbering routine to open up space to
Insert new sentences and paragraphs, and an
Inverse video screen function.

$20 16K cassette

DATAPLOT

Plot stock prices, interest rates, scientific
data, etc. with this program. DATAPLOT
plots positive and negative free formatted
data stored in REM statements. Draws and
labels the axes, titles plots and connects data
points. DATAPLOT will also draw figures,
plot from an equation and plot on a grid if
necessary. Use with your printer fora copy of
your plot. |

$10 16K cassette

STRING

A routine you can add to your programs to
search for commands, words, and phrases.
Perfect for locating phone numbers, program
statements, etc.

$2 2K listing

INVERSE VIDEO

Software machine code routine to reverse
your screen to white characters on a solid
black background.

$4 1K listing

Call (303) 441-0110 for Visa/MC Orders. |

Please rush me the following programs: i
O TEXT & PRODIR O STRING i

O TEXTII O INVERSE VIDEO
0 DATAPLOT

i Enclosed is $_______ or charge my i
I VISA O MASTERCARD O |
CARD NO EXP. DATE __|
| SIGNATURE

NAME:
(Please Print)

ADDRESS
CITY/STATE/ZIP:
P.O. Box 8005, Suite 231

p eak Boulder, CO 80306-8005 |

|
COMUNA Quisiera ARCUP S MowtOD Vale MIU

Figure 4. Transistor Switches (Total of 16).
2N2222

T35V
(RX-81
output
activated)

R1 220 Ohm 1/4 watt

To DIP relay
coil (gnd side)

gnd

connected by a blue with white stripe
wire to finger 10 of a short PC board
which is plugged into the circuit loads,
depending on the size of the DC motor or
solenoid driven.

Large DIP mounted relays of sufficient
amperage can be used but they can be
expensive ($4-5 each). I found some min-
iature 6 volt DPDT relays rated at 3 amps
which were cheaper and worked quite
well. One source is the All Electronics
Corp. at only $1.75 each. Sixteen to
twenty of these can be packed ona 4 x 5

. inch PC board, although the more expen-

Figure 5. DIP Relays (16 total).

-in* +5V CSV o TSV
out**

D2 1N4148

C1 .01 MFD, 10V

**For DIP #1 this would be wired to
connector L.
**For DIP #1 this would be wired to
connector 10.

sive high amp rated contact DIP relays
would not have to be packed so closely.

An example of both the forward and
reverse relays is shown in Figure 6. They
are wired together to prevent accidental
shorting of the output to the motor. Each
of the two relays for each motor (one for
forward and one for reverse) provides
opposite polarity power. If you made no
special wiring provision, it would be pos-
sible to activate both relays at the same
time and cause a direct short circuit be-
tween +12 volts and ground. Two extra
wires between the two relays, along with
a modification of a direct hookup, protect
against this.

If you look at Figure 6, you will see
that the coil input (+5 volts) to the right-
hand relay coil (relay #1) will not cause
the coil to be activated unless relay #2
(lefthand relay) is not activated. This is
because the coil of relay #1 has no ground
to complete the circuit unless relay #2 is
in the normally closed position. Notice
that the ground for relay #1 coil is sup-
plied through the normally closed contact
of relay #2. This way, even if both the
reverse and forward circuits are activated
at the same time, only one will work.

Also note the diode and capacitor pro-
tection on these relays. This feature is
especially important as the unloading of
these relays introduces a lot of unwanted
into the electrical circuits.

For some motors in your robot the 12
volt output of the relays in Figure 6 will
be hooked directly to the motor leads.
However, you may wish to install limit
switches on the mechanism of some motor
drives such as the arm elbow motor. The
limit switches are normally closed

July/August 1983 © SYNC

Figure 6. 5 Volt DPDT Relays (16 total).

Common

T- 12V T
A |n
D2
T 5V in
(17)**
IL
mm
"EREOT
T- 12V out
(V **)
D1 1N4002
D2 1N4148
D3 1N5401
C1 .01 MFD 25V
C2 22 MFD 35V

contact microswitches. A simple but ef-
fective limit switch circuit using two
diodes and a four terminal, terminal strip
is depicted in Figure 7. If you happen to
get it wired backwards (50/50 chance),
just reverse either the 12 volt input leads
or reverse the motor output leads. .

Input Stimuli

Before we turn to software, a few words
about input stimuli to the input board.
First, the input board is the same board
that is used for output, the Zodex RX-81
in this case. The RX-81 provides eight
input lines and a ground. To input a signal
to DO, or as I refer to it, 1-1 (input line #1
of RX-81 board #1), you just connect the
input line to ground.

For my robot I installed normally open
connect microswitches to the exterior of
the robot with spring wire extensions
covered with foam rubber pads. The
bumper switches include one as a front
bumper, one as a right bumper, and one

July/August 1983 ° SYNC

LÀ
LE
3 NC

Coil

Common

"mM +12V
D3
< Ira]
D2
«i 4 |
+5V in C2
(20)*

tere
io

+12V out
(W)*

NC = Normally closed contact.
NO = Normally open contact.

*Wired to this connector if relay #1.
** Wired to this connector if relay #2.

as a left bumper. I actually installed two
sets of two front bumper switches each,
one set with a spring wire horizontally
between them and another set with a
spring wire vertically between them. This
arrangement gives a larger striking area if
the robot runs head on into something.
The obvious expansion of the input switch
system would be the addition of other
types of sensors such as an ultrasonic
range measuring system, like the one from
a Polaroid camera focusing system, avail-
able for about $130. |

An alternate way to accept input com-
mands to the computer is to wire the
external microswitches sensors as keys
on the ZX81 keyboard. This method
works, but it is not totally satisfactory.
The computer can be set up to scan the
keyboard for specific key inputs, but the
problem arises when two keys (or micro
switches) are closed at the same time.
This can easily happen if the robot works
its way into a corner and hits the front

and side sensors together. The computer
will not normally accept any keyboard
input if this happens and it could even be
seen as an illogical input and blow the
program.

With sensors wired to the RX-81 par-
alled input board a program can be writ-
ten to accept any combination of simul-
taneous sensor inputs at the same time,
and recognize them. More on that in the
software explanations.

Writing the Software

When your robot motors and bumper
switches are wired up to the ZX81 com-
puter as described, you are ready to start
writing software to "control the world" or
at least the world of your robot. All pro-
grams are for 8K ROM. The second listing
will require 16K RAM.

The data sheet that comes with the
RX-81 explains a few programming in-
structions to get you started, but my pro-
grams written for direct robot control will
be explained in detail. All programs
start with the line of machine language in
the. REM statement (do not forget to
delete the first REM statement containing

Figure 7. Limit Switch Hookup.

To limit To limit
switch switch
E EN
C p.
12V
Inputs
from relays
To motor leads
D1,D2 1N4002
25

INTRODUCING
EPROM SOFTWARE FOR
TIMEX-SINCLAIR COMPUTERS

MEMOTECH INTRODUCES THREE NEW
SOFTWARE PACKAGES FOR YOUR

TIMEX-SINCLAIR.

All Memotech software is compatible with both the ZX-81 and
TS-1000 computers and comes in its own Memopak case that plugs
directly into your computer.

MEMOCALC

Now there's a powerful tool to assist you with reports and financial
forecasts. Memocalc, our spreadsheet analysis software, on EPROM,
enables TS-1000 and ZX-81 users to perform complex number crunching
routines with ease. With Memotech's 64K RAM a table of up to 7000
numbers with up to 250 rows or 99 columns can be specified. Quick
revisions can be achieved by entering new data to your formula. Then,
by entering the command CALCULATE, the information is reevaluated
and displayed.

Spreadsheet analysis started as an aid to cash-flow analysis, but
this powerful tool has now been generalized and Memocalc with it's
special ability to perform interactive calculations is invaluable in the
performance of numerical tasks.

MEMOTEXT

The Memotext word processor, on EPROM, brings commercial
standards of text editing to your computer. Text is first arranged in 32
character lines for the screen with comprehensive editing facilities. On
output the user simply chooses the line length for printing and the
System does the rest. Used with our Memopak printer interfaces, it

enables output with 80 character lines, upper and lower case, and single
and double size characters.

MEMOPAK ASSEMBLER

The Memopak Assembler, on EPROM, is for those who want to roll
up their software sleeves and get down to controlling precisely the power
of their computer. It lets you code and edit a source program in the Z80
language, and then assemble it into machine code. You can now write
flexible and economical programs, tailor-made in every detail to your own
needs, and free from the extravagant use of time and space that goes
with the basic high level code.

The editor mode allows you to code directly in the right format,
manipulate individual lines and control the exact placing of source and
machine code. Routines may be merged or listed (even to a commercial
printer with our printer interfaces).

The Assembler mode handles all standard Z80 mnemonics,
numbers in hex or decimal, comments and user-selected labels. Be an
expert software engineer through this pack and it's clear documentation.

ORDER AT NO RISK.

All Memotech products carry our 10 day money back guarantee. If
you're not completely satisfied, return it within ten days and we will give
you a full refund. And every Memotech product comes with a six month
warranty. Should anything be defective with your Memotech product,
return it to us and we will repair or replace it free of charge. Dealer
inquiries welcome. To order any Memotech product use the order
coupon or call our toll-free number 800/662-0949.

TS-1000 is a registered trademark of Timex Corp.

FROM MEMOTECH... THE WORLD'S LARGEST
SUPPLIER OF ADD-ON PRODUCTS FOR
TIMEX COMPUTERS

Code: SY-78

Mail To: Memotech Corporation, 7550 West Yale Ave., Denver, CO 80227

Memocalc

Memotext

Memopak Assembler

Shipping and Handling

Price* Qty. Total
$49.95
49.95
49.95
4.95 $ 4.95

Tax (Colorado residents only)

TOTAL

C Check

[C] MasterCard — [ ] Visa

*All prices quoted in U.S. dollars. Prices and specifications subject to change without notice.

Account No.

Exp.

Name

Address

EANES co EPUM CELO Y EOM A OO

for eS CT CE Gaited Lab Tr oe Le ee

TIMEX MAKES THE
COMPUTER,
BUT WE MAKE IT TICK.

If you own a TS-1000 or ZX-81 computer and want to bring out the power within it, you'll want Memotech. From easier input to high
quality output and greater memory, Memotech makes the add-ons you demand. Every Memotech peripheral
comes in a black anodized aluminum case and is designed to fit together in “piggy back" fashion enabling you — 20
to continue to add on and still keep an integrated system look. Printer Iterace

High Resolution een Memopak RAM

MEMOPAK RAM All Memopak RAMs are directly addressable, user transparent, are neither switched nor
paged and no additional power supply is required. You can also choose the Memopak RAM which is just
right for your needs. From economy to power. 16K RAM The Memopak 16K RAM is the most
economical way to add memory to your TS-1000. It is fully compatible with the Timex or Memotech 16K
RAMs to provide you with up to 32K of RAM. The 16K RAM also offers additional add-on capabilities
through its “piggy back” connection. — 32K RAM The 322K Memopak enables you to execute
sophisticated programs and store large data bases and like the 16K RAM is fully compatible with Timex’s or
Memotech’s 16K RAMs to give you a full 48K of RAM. 64K RAM The 64K Memopak is powerful
enough to turn your TS-1000 into a computer with capabilities suitable for business and educational use. It
is J accepts such BASIC commands as 10 DIM A (9000). |. MEMOCALC Migiogte, our SPEM MONS
software, enables TS-1000 users to perform complex number crunching routines with ease. With p~ cm
the 64K RAM a table of up to 7000 numbers with up to 250 rows or 99 columns can be specified.
Quick revisions can be achieved by entering new data to your formula.
MEMOTECH KEYBOARD For ease of operation, the Memotech keyboard is a high quality
standard typewriter keyboard, with TS-1000 legends. The keyboard is cable connected to a buffered
interface which is housed in a standard Memopak case and plugs directly into the back of the
TS-1000 or other Memopaks. |. MEMOPAK HRG The Memopak High Resolution Graphics, with
up to 192 by 248 pixel resolution, enables display of high resolution “arcade game" style graphics
through its resident 2K EPROM, programmed with a full range of graphics subroutines.
CENTRONICS PARALLEL AND RS232 INTERFACES
Memotech's Interfaces enable your TS-1000 to use a wide range of
TUUM compatible printers. The resident software in the units gives the
peame ASCII set of EE Both Memopak Interfaces provide lower case character capabilities and.
up to 80 column printing. The RS232 Interface is also compatible with modems and terminals.
SEIKOSHA GP 100A PRINTER The Seikosha GP 100A uses a 5x7 dot matrix printing format with
ASCII standard upper and lower case character set. Printing speed is 30 characters/second with a

maximum width of 80 characters. The printer uses standard fanfold paper up to Bueno ae ae Ges bie e De RU ae
?- y 2 inches wide. The GP 100A is offered as a package including cable and ub CE E a :
| interface. Other printer packages are also | VUE wor T
available through Memotech. | 32K RAM 99.95
ORDER AT NO RISK. All Memotech | CES =
Memocalc 9.95
products carry our 10 day money lk Sener g ers ES
guarantee. If you're not completely | High Resolution Graphics 99.95
satisfied, return it within ten days and we , Centronics Parallel Interface 74.95
will give you a full refund. And every [EE saien mm
Printer Cable 19.95
month warranty. Should anything be Shipping and Handling 495 $ 495

defective with your Meteor Ed return it to us and we will repair or replace | Tx (Colorado residents only
it free of charge. Dealer inquiries welcome. To order any Memotech product use
*All prices quoted in U.S. dollars. Prices and specifications subject to change without notice.

the order coupon or call our toll-free number QOQ / 662- 0949. | **Plese add an additional $5.00 for printer shipping charge

| [.] Check (J MasterCard L] Visa

TOTAL $

TS-1000 is a m trademark of Timex Corp. E Exp.
FSS SS ERE E SES So: DNR Ti I awe MEN CORRS A
= S sS SSS 2252 5~“S3 = IN Ph be
& dub S055 DUES pe M aa
CORPORATION Ls
| city State Zip
7550 West Yale Avenue, Denver, Colorado 80227, 303/986-1516, TWX 910-320-2917 Ban es E VUE NOM ee MEER Sedes A

r ——n——À'— —ÀÀ—Á QAAE EEEEDLILZIDIDIÓLSILUZLLIZULÁGGO-JDÓUÜCÉLCEKAL€ BL LELIOCILLCLIDCLUÓLTÓLOBGIOOLLOOL OR?IAY?ILULCL1LALILOOG(SCLQLLOOLLOCGeEO LU€LU'LLULÁ/OLOLRUÁÓÁLUÁAUALLUEÁLEL ALCLLKIXLELLIIGLGLL OGLU/LZLCCLLCAAAXLEILLALLUAAAI S ee eee

Figure 8. Software Commands.

$ Function Relay Output POKE A, POKE B,
Body left 1 i 14 z
Body right ds 1-6 Nat y
L.. wh. fwd Ri Fet if T.
Il. wh rev 4} bong e. =
Ro owh fwd Rd Lee 4 £
Io wh rev É ]-4 c 7
L «h dn y E i ^
Il. sh up 1o e P &
Rosh dn i4 dA zb ^
R sh up 12 c4 E &
L. el dn i oot 16 6
Il. el up 14 ee se &
R el up a roy 64 &
k el dn 18 Ec iag &
RE hand clase! 19 por 54 7
R hand open | 20 1-0 Lcd $
SNE 5 SES a I UISISCAN 2a ps Nae ARR RI
Switch Input IF IN= POKE B,
Front bumper l:-I 1 7
Left bumper (ded = v
Right bumper le 4 7
Right palm irg he 7

(Note: A = 16522 and B = 16524)

LET YOUR ZX81/TIMEX 1000 WORK FOR YOU!!

PERSONAL AND BUSINESS PROGRAMS:
Are on cassette, are menu driven, run with or without a printer and save on tape automatically.

SALES FILES 16K or 64K: Holds (150/16K) (600/64K) products w/wholesale and retail prices. — Shows separate wholesale
and retail totals and amount of profit in up to (25/16K) (100/64K) different accounts. — Records inventory automatically or
manually. — Totals sales tax. — Cash register mode totals, identifies, adds sales tax, and keeps records for your bookkeeping.
Prints a list of products, accounts, inventory and sales slips with printer.

*** A must for any small business ***

CHECKING 16K or 64K: Lists (25/16K) (100/64K) deposits Showing amount and date entered. — Lists (80/16K) (500/64K)
checks and displays check number, date and payee. — Lists by account total of checks written. Keeps running total of checks
written and balance left in account. — Adds interest and subtracts service charges. — Search for a check by number, name,
date or amount. — Print a list of deposits, accounts, and checks with printer.

*** Great for tax records ***

INVENTORY 16K or 64K: May be used for everything from keeping an accurate inventory for your business, to your personal
record collection. — Holds up to (150/16K (750/64K) items w/comments for each. — Comments may be used for serial
numbers, dates, prices or location. — List all items, search for single item, change or delete any item. — Sort items in
alphabetical or numerical order. — Prints a list of items, quantities and comments.

*** Everyone should have an inventory of household items in case of fire or theft. ***

MAILING LIST 16K or 64K: Holds (100/16K) (425/64K) names, addresses and telephone numbers. — Search by name, city,
zip code, or phone number. — Will sort by name, city, or zip code in alphabetical or numerical order. — Lists all names,
changes or deletes. — Prints list of names or names and addresses or address labels if they are available for your printer.
*** A valuable tool for your home or business ***

APPOINTMENT CALENDAR 16K: May be used for everything from reminding you of birthdays to business appointments.
— Just enter the date and list up to (8) appointments per day for up to (31) days. — Lets you change or delete any appointment.
— Print a list of appointments for day or month. — Save all appointments on tape.

. *** Keep a permanent record of past appointments ***

Send for free catalog of personal, business and educational programs.

DEALER INQUIRIES INVITED

HEATH COMPUTER SERVICES
950 East — 52 South
Greentown, IN 46936
Phone 317-628-3130

Any three $9.95 tapes for $24.95
Add $1.00 per tape for shipping.
Indiana residents add 5% sales tax.
Send Cert. Check, M.O., Visa or
MasterCard No. w/Exp. Date.

the program name before running the
program) followed by POKE 16517, 79.

To activate an output line you first
POKE the binary number for the line,
then POKE the number of the output
board (if you have more than one board)
and the activate the command with an
OUT USR statement. For example, if you
wanted to activate output line #3 on an
output board wired as “OUT 7" you would
write the program as follows:

100 POKE 16522,4
(addresses line #3)

110 POKE 16524,7
(addresses board wired as OUT 7)

120 LET OUT=USR 16521
(activates command)

As listed in Figure 8, this would make
the right wheel move the robot forward.
To make the right and left wheels go
forward use the following lines:

130 POKE 16522,5
(addresses line #1 and #3 together by
adding their binary numbers 1 + 4)

140 POKE 16524,7
(addresses board wired as OUT 7)

150 LET OUT=USR 16521
(activates command)

To turn these motors off, POKE 0, as
follows:

160 POKE 16522,0
(deactivates all output lines)

170 POKE 16524,7
(addresses board wired as OUT 7)

180 LET OUT=USR 16521
(activates command)

Memory Saving Shortcuts

As you might have gathered from Fig-
ure 8, there are some memory saving
shortcuts to this programming. If you add
the following LET statements earlier in
the program, you save memory and make
the program statements easier to type
into the computer.

10 LET A=16522

20 LET B—16524

30 LET C=16521

The above lines 100-180 can now be
shortened to:

100 POKE A,4

110 POKE B,7

120 LET OUT=USR C

130 POKE A,5

140 POKE B,7

150 LET OUT=USR C

160 POKE A,0

170 POKE B,7

180 LET OUT=USR C

Other refinements are possible to

further save program steps. For example,
lines 140 and 170 can be omitted because
location B (16524) remains POKEd
throughout the sequence. If you change
from the OUT 7 board to a second board
wired as OUT 6 and back again, the
POKE 16524 step would have to be in-
cluded each time so that the proper board
would be addressed.

July/August 1983 ° SYNC

NOW. A TS1000/ZX81
PUSH-BUT TON

KEYBOARD

FOR UNDER $2000.

At last theres a really cheap but
efficient way of ironing out the T51000/ZX8I's
only real bug: its keyboard. The Filesixty

Buttonset offers Mor ETHER ap ue
m A full-travel calculator-type moving
keyboard for only $19.50.
m installed in seconds. [he peel- off
adhesive backing means you just register into — "sseseese 00 Ut YOn
position and Dress. [ Cheques/ money orders made payable to Filesixty Ltd.
m No messy labels, dismantling or | Please send me (qty) Buttonset(s) |
soldering. | at $19.50 each (inclusive of postage & packaging). |
m 3 groups of colour keys to pick out , Toal $- 1 1 1 1 1 111 BtocKcAPmus
shift, numerals and newline. BEL TEE
m Precision moulded in ABS to match — | address |
your TS1000/ZX8l, with contrasting legends | |
for maximum legibility. | state 1

| "J"
ULL

| Bis I
| In |
n

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| ntt |
wi} f
m

I
Ww

Orders to Filesixty Ltd., 25 Chippenham Mews, London W9 2AN, 7
England. Tel: 01-289 3059. Telex: 268 048 EXTLDN G 4087. Lh o o 2

Parts List
(Parts with common part numbers have
been omitted from this list, i.e., trans-
istors, ICs and resistors)

Power Supply

2300 MFD, 33VDC capacitor. Jam-
eco # 2300@33V.

5k ohm adjustable pot (10 turn).
Mouser # 593-830P.

125 uH, 3.5 amp Hash Choke.
Mouser # 542-5252.

DIP Relay Board

5v BIP relay. Mouser # 518-5002105.

PC board. Hobby board. Digi-key #
K160-ND.

5 volt DPDT relay board

5v DPDT relay. All Electronics #
FRLY-6.

PC board (Same as DIP relay board
above).

Transistor switch board
PC board (same as PC board above).

Circuit board holder
Edgeboard connectors. Digi-key C1-
22.

Intermediates connector (Photo 2)

PC board (same as PC board above).

Edgeboard connectors (one con-
nector can be cut into the size shown).
Digi-key # C5-50.

Computer Continuum expansion
board

If the bare board is purchased, a
parts list is provided.

Zodex RX-81
If the bare board is purchased, a
parts list is provided.

Addresses:

Jameco Electronics, 1355 Shoreway
Road, Belmont, CA 94002.

Mouser Electronics, 11433 Wood-
side Ave., Santee, CA 92071.

Digi-key Corporation, P.O. Box 677,
Thief River Falls, MN 56701.

All Electronics Corp., P.O. Box
20406, Los Angeles, CA 90006.

Computer Continuum, 301-16 Ave.,
San Francisco, CA 94118.

ZODEX, East Hill, Oakham, MA
01068.

Robotics Note

The Radio-Electronics series on build-
ing a robot is available in reprint form for
$12 plus $1 s&h from: Radio-Electronics,
Reprint Dept., 200 Park Ave. South, New
York, NY 10003. Readers who want to
communicate with the author Bruce
Taylor may do so in care of SYNC.

Test Program

An example of a test program is pro-
vided in Listing 1. This program activates
a single output line and then stops. If you
enter CONT, it will then turn the output
line off and stop again. Enter CONT, and
it will activate the next output line and so
forth, repeating the process.

The input line activation is a little
simpler. You first ready the input for
activation and then use IF statements to
look for the proper input to activate a
response. For example:

500 LET IN=USR 16514
(readies input for activation)

510 IF IN=1 THEN GOTO 100
(if input line #1 is activated, the program
jumps to line 100)

If more than one input board is used, a
POKE 16524 line would have to precede
the USR line to identify the board in
accordance with how it is wired. In my
robot only one board is used for input as
eight input lines are more than enough.
Also, the same memory saving techniques
can be used

LET F=16514

A sample routine to scan for inputs is
as follows:

900 LET IN=USR F

910 IF IN=1 THEN GOTO 100

920 IF IN=2 THEN GOTO 200

930 IF IN=4 THEN GOTO 300

940 GOTO 900

Listing 1.

1 REM “RX5i“

e REM c=" J a TAN v PEEK FTAN
10 POKE 16517,79
2@ LET A=16522

J
gaz
uo
;

aod OP

390 GOSUB 578

420 oP

110 POKE R,6564

420 POKE B

430 LET OUT-USR C
4480 STOP

450 GOSUB 578

460 STOP

470 POKE RH.125
4&0 POKE 6,7

+90 LET QUT =USR C
S500 STOP

Sie GOSUB 570

S20 STOP

sse KE ALG

S540 POKE 6.6

5580 LET c
560

L
S00 RETURN

Program to Move the Robot Forward

Listing 2 is a portion of the program
that is currently in my robot. It moves the
robot forward (R + L wheel fwd), while
scanning for hits on the microswitch sen-
sors in the form of inputs. If the right
bumper input is activated, the robot stops
its forward motion, backs up, turns to the
left about 30 degrees and continues for-
ward, again sensing for bumper inputs.
The sequence is similar for a left bumper
input except that it turns to the right
about 30 degrees before continuing.

The sequence for a front bumper hit is
a little different in that a random number
generator is used so that 50* of the time
the robot turns right 60 degrees and 50*
of the time it turns left 60 degrees before
continuing forward. A counting step is
also included as part of the input scanning
routine so that the robot moves forward
for about nine seconds and then generates
a random number between zero and one.
One third of the time it will stop and go
into a body rotating and arm demon-
stration subroutine.

Timing Techniques

Several timing techniques are used in
the program. PAUSE is a good technique
when interruption is not required such as
in arm movements, where there is no
danger of hitting or running into some-
thing. The FOR-NEXT loop is a good
technique for input scanning when there
is a possibility of a collision with another
object. A counting technique as a loop
also works well in this situation.

The Expansion Boards

Do not be scared off by this project if
you are not willing to go the full expansion
route with a board such as the Computer
Continuum product. The Computer Con-
tinuum expansion board was chosen be-
cause of its 3 amp capacity for 5 volt
supply as additional circuits are added to
the robot.

The Zodex RX-81 board (also available
assembled as a “Control Board for 8
devices") can be plugged directly into the
ZX81 bus just as the printer and 16K
RAM are plugged in. If you want to add
more boards, a simple Y connector will
do the trick.

However, if you want to use the Com-
puter Continuum expansion board, you
must know which of the two versions of
the board you have, neither of which can
be used as I have described without some
modification. The earlier version of the
board will accept the Zodex board plug-
ged directly into an expansion edge con-
nector (50 pin, .1 inch centers) soldered
to the CC board, but the logic will not
work without an additional simple de-
coder circuit you will have to build. The
Sinclair printer will not work without this
decoder circuit either.

July/August 1983 © SYNC

The newer version of the CC expansion
board comes with the decoder circuit
built into the board, but the expansion
pad pinout has been reversed so that the
Zodex board can no longer be plugged

an RNS oe

2 REM «-9*J a TAN Y PEER Fran.
10 POKE 16517.79

2a GOTO 2050

430 GOSUB D

see GOTO 2210

Sia STOP

S28 REM RANDOM SELECT

538 IF RND¢.67 THEN GOTO 2259

810 FOR W=1 TO 28
S20 IF W=28 THEN GOTO 5498
830 NEXT U

930 LET IN=USR F
94ð IF IN=2 THEN GOTO Soe

950 IF IN-1 THEN GoTo

960 IF IN=3 THEN GOTO 3996

970 IF W=12 TREN GOTA 1818

UB G
FOR U-1 TO i8
1050 IF U-ib THEN GGTOG liere

directly onto the CC board. The Zodex
board can be plugged onto the bus con-
nection for the 16K RAM, but then you
have to work out another location for the
RAM.

Listing 2.

1170 PAUSE 89

1438 IF IN=i25 THEN GOTO i466
1440 IF 1-309 THEN GOTO i468

1760 PAUSE 1,0

1810 LET IN-USR F
1830 PRUSE 496

20408 GOSUB D

2060 LET R-15522
sa70 LET B-16524
2080 LET C-16521
2090 LET D-19586
2100 LET E-2G9
2110 LET F-15514
2120 LET G-2390
21530 POKE a.@
2id@ POKE B.

21580 LET DOuUT- usr c
21580 PORE A.B
21780 POKE 5.5

2230 LET OUT-USR C
2240 LET TN=8

#225@ LET TN-TIN-«*1
2268 BET eee ate F

S318 IF IN=5 THEN GOTO 350

EN GOTO 38
3 IF TN-298 THEN SOTO Sse
4e GOTO 2250

July/August 1983 © SYNC

The easiest way to tell the two versions
of the CC board apart is that the newer
version has a 74LS27 IC chip located next
to the optional LM323 voltage regulator
while the older version does not. By the
way, I highly recommend using the op-
tional voltage regulator, because it lets
you bypass the voltage regulator in the
ZX81 and you can kiss overheating prob-
lems goodby forever.

If you have the older version you can
plug the Zodex board directly onto an
edge connector on the CC board. Al-
though there are several ways to install
the required decoder circuit, I recom-
mend writing to Computer Continuum
and asking for a copy of the documen-
tation sheet for the new version. Figure 1,
schematic, and Figure 2, legend, is all you
will need. Then install the 74LS27 just as
it is installed on the new version. It can
be installed in the same spot as the new
version with an IC socket, a few jumper
wires, and some cuts in the circuit board
foil. If you do this, you have essentially
the newer version.

If you have the newer version of the
Computer Continuum board, the decoder
is already installed. If you do not want to
solder the Zodex board(s) directly to-
gether, you will have to build an inter-
mediate connector. One solution is shown
in Photo 1. The pinouts of the .1 inch
center edge connectors are jumpered to
the correct fingers of the .156 inch center,
4 x 5 inch PC board.

Robot Expansion Plans
I hope I have helped you get started

in a robot project. If you are serious about
a self-contained robot, I recommend the
Radio-Electronics robot reprint articles
as a source of much useful information.
The whole idea of this project to inter-
nally control a robot with a ZX81 com-
puter is to demonstrate how much power
the little computer really has. I have not
yet maxed out the 16K RAM, although I
am ready with a 16K Byte-Back module
to add to the Sinclair 16K RAM pack.

Future robot expansion plans include
measurement of robot movements and
feedback of this information into the com-
puter memory so that the robot can learn
as it moves about and functions. A digital
voice and voice recognition circuit is also
possible since these circuits are becoming
available in the $50-150 range. The ZX81
can be expanded to do an almost limitless
number of functions without great cost.

And finally, even if you go with a full-
blown robot project, you do not have to
sacrifice your ZX81 or TS1000 to dedi-
cated robot control. A keyboard plug and
an extension of the video plug have been
added to my ZXS81 in the robot. The
robot can stop and perform as a regular
computer by simply plugging in an ex-
ternal keyboard and video display.

AN me e A AA E E SD PEA RN HUE DES SAGE SE a a Ne a NEPE EEE DEIER EA ESANA EE T pP ik LE

So You Wished You Had Bought A TS2000

The Challenge of the TS2000

How would you like to have a computer with a color video
display of fifteen colors, quality sound, high resolution,
unlimited character sets, and a dual joystick interface? How
would you like a system in which you do not have to worry
about expansion? If you have a ZX81 (or ZX80 with the 8K
ROM), you could have such a system—the COLORSINSI.

Since ZX81 hardware and software are incompatible with
the TS2000 expansion bus, many of us who have made sizeable
investments in these items will not be able to justify purchasing
the new product, as is the case with me.

This article sets forth my answer to the challenge of the
TS2000 in a design to give the ZX81 the capability of having
all of these features at a very reasonable cost. We will cover
the system features, circuitry background, applications, con-
struction of the board, testing and debugging, and program-
ming. Many of the debugging suggestions are useful in other
applications.

System Features

Most peripherals on the secondary market provide the user
with a new capability or function. They normally are not
designed or sold to be interactive with the user or the machine.
This system has been designed differently; it has the user in
mind. By building or purchasing this system, you are not only
adding the features mentioned, but are actually opening your
system to be anything that you want it to be.

Figure 1 compares the COLORSINS1 with the TS2000 in
features, ease of use, and expandibility.

The two systems use entirely different approaches in cre-
ating their displays. The TS2000 uses a new ULA to produce
color, with the high resolution being a product of new software.
The COLORSINS81 uses a dedicated IC to produce and
maintain a display. It requires none of the user memory! It
has its own 16K of video memory to store images and pages
in. As you will see later, this protected memory has many
other uses.

The 6-slot motherboard includes two slots which will accept
Radio Shack stocked boards. For interfacing your homebrew
circuits to the Sinclair I have included 8 memory-mapped
select lines. These are for the exclusive use of experimenters
and hobbyists. |

Daniel G. Roy, 99 Andover St., Lawrence, MA 01843.

Daniel G. Roy

So that the user does not have to "call" the capabilities of
the board when required, the computer jumps to the system
PROM, does the initialization of the system, loads the color
display into memory, enables the sound, checks for joystick
activity, and prompts the user with a "ready" on the screen.

Because the system PROM does the initialization, 64K
RAM packs are fully supported. POKEing the Sinclair
RAMTOP variables to have access to the upper half of
memory is not necessary.

Since this system does not depend on the Sinclair to
maintain a display, the computer may be run exclusively in
the FAST mode. However, if you want both displays at the
same time, you could run the system in the SLOW mode and
use two TVs.

Figure 1. Comparison of COLORSINS1 and TS2000 Features.

COLORSINSI TS2000
Number of colors available 15 + 8
transparent
Maximum pixel resolution 256 0 192 256 X 192

Sound range (octaves) 8 10

Sound produced by: speaker piezoelectric
element

Number of joysticks 2 (4) N/A
Characters/line 32-40 32
Ram available to user 56K 48K less

: 3 display
Additional video ram 16K N/A
Program merging supported ^ s eS no
Sprites available to user 32 N/A
User definable characters 256-768 21
Character sets redefinable yes no
Expansion slots provided 6 1 (the bus)
Interface circuitry provided 8 select lines N/A

New Commands
The system adds 17 new commands (see Figure 2), including
READ, DATA, and RESTORE. However, after you discover
the power of the other commands, you will consider these to
be less important. :
You will now be able to MERGE and CHAIN programs,
whether in Basic or machine language. Instead of writing

July/August 1983 * SYNC

AARDVARK — THE ADVENTURE PLACE

TRS-80 COLOR
WE CARRY MORE THAN ADVENTURES!!

MAXI-PROS WORD PROCESSING ue"

. The easiest to use word processor that I
know of. Has all the features of a major word
processor (right and left margin justification,
page numbering, global and line editing, single,
double, triple spacing, text centering, etc.) at
a very cheap price because we wrote it in
BASIC. Includes 40 page manual and learning
guide. Easily modified to handle almost any
printer combination. Available on disk or tape
for VIC20, COMMODORE64, and TRS-80
COLOR computer. Requires 13k RAM on
Vic, 16k EXTENDED on TRS-80 COLOR. RS
$19.95 on tape $24.95 on disk. we
GENERAL LEDGER — Complete bookkeep-
ing for a small business. Disk required. For
Vic20 (13k), Commodore64, TRS-80 COLOR
(16k EXTENDED). $69.95 (Send $1.00 for
manual before ordering.)

LABYRINTH — 16K EXTENDED COLOR
BASIC — With amazing 3D graphics, you fight
your way through a maze facing real time
monsters. The graphics are real enough to
cause claustrophobia.

Similar game for Timex/Sinclair 16k - hunting
treasure instead of monsters $14.95.

ADVENTURE WRITING/DEATHSHIP by
Rodger Olsen — This is a data sheet showing
how we do it. It is about 14 pages of detailed
instructions how to write your own adven-
tures. It contains the entire text of Deathship.
Data sheet - $3.95. NOTE: Owners of TI99,
TRS-80, TRS-80 Color, and Vic 20 computers
can also get Deathship on tape for an addi-
tional $5.00.

Dealers — We have the best deal going for you.
Good discounts, exchange programs, and fac-
tory support. Send for Dealer Information.
Authors — Aardvark pays the highest commis-
sions in the industry and gives programs the
widest possible advertising coverage. Send a
Self Addressed Stamped Envelope for our
Authors Information Package.

COMMODORE 24

VIC-20

ADVENTURES — Adventures are a unique
form of computer game. They let you spend
30 to 70 hours exploring and conquering a
world you have never seen before. There is
little or no luck in Adventuring. The rewards
are for creative thinking, courage, and wise
gambling — not fast reflexes.

In Adventuring, the computer speaks and
listens to plain English. No prior knowledge
of computers, special controls, or games is re-
quired so everyone enjoys them —even people
who do not like computers.

Except for Quest, itself unique among Ad-
venture games, Adventures are non-graphic.
Adventures are more like a novel than a comic
book or arcade game. It is like reading a par-
ticular exciting book where you are the main
character.

All of the Adventures in this ad are in Basic.
They are full featured, fully plotted adventures
that will take a minimum of thirty hours (in
several sittings) to play.

Adventuring requires 16k on Sinclair, TRS-
80, and TRS-80 Color. They require 8k on OSI
and 13k on VIC-20. Sinclair requires extended
BASIC. Now available for TI99.

TREK ADVENTURE by Bob Retelle — This
one takes place aboard a familiar starship and
is a must for trekkies. The problem is a famil-
iar one — The ship is in a “decaying orbit”
(the Captain never could learn to park!) and
the engines are out (You would think that in
all those years, they would have learned to
build some that didn't die once a week). Your
options are to start the engine, save the ship,
get off the ship, or die. Good Luck.

Authors note to players — | wrote this one
with a concordance in hand. It is very accurate
— and a lot of fun. It was nice to wander
around the ship instead of watching it on T.V.

DERELICT by Rodger Olsen and Bob Ander-
son — For Wealth and Glory, you have to ran-
sack a thousand year old space ship. You'll
have to learn to speak their language and
operate the machinery they left behind. The
hardest problem of all is to live through it.

Authors note to players — This adventure
is the new winner in the “Toughest Adventure
at Aardvark Sweepstakes''. Our most difficult
problem in writing the adventure was to keep
it logical and realistic. There are no irrational
traps and sudden senseless deaths in Derelict.
This ship was designed to be perfectly safe for
its’ builders. It just happens to be deadly to
alien invaders like you.

Dungeons of Death — Just for the 16k TRS-
80 COLOR, this is the first D&D type game
good enough to qualify at Aardvark. This is
serious D&D that allows 1 to 6 players to go
on a Dragon Hunting, Monster Killing, Dun-
geon Exploring Quest. Played on an on-screen
map, you get a choice of race and character
(Human, Dwarf, Soldier, Wizard, etc.), a
chance to grow from game to game, and a 15
page manual. At the normal price for an Ad-
venture ($14.95 tape, $19.95 disk), this is a
giveaway.

Please specify system on all orders

SINCLAIR/TIMEX

TI99

PYRAMID by Rodger Olsen — This is one of
our toughest Adventures. Average time
through the Pyramid is 50 to 70 hours. The
old boys who built this Pyramid did not mean
for it to be ransacked by people like you.
Authors note to players — This is a very
entertaining and very tough adventure. | left
clues everywhere but came up with some in-
genous problems. This one has captivated
people so much that | get calls daily from as
far away as New Zealand and France from
bleary eyed people who are stuck in the
Pyramid and desperate for more clues.

MARS by Rodger Olsen — Your ship crashed.
on the Red Planet and you have to get home.
Y ou will have to explore a Martian city, repair
your ship and deal with possibly hostile aliens
to get home again.

Authors note to players — This is highly
recommended as a first adventure. It is in no
way simple —playing time normally runs from
30 to 50 hours — but it is constructed in a
more "open" manner to let you try out ad-
venturing and get used to the game before
you hit the really tough problems.

s ARN

Mules
Bees! ‘a Sn a. | '

2 —
Ee uk 220
me

QUEST by Bob Retelle and Rodger Olsen —

THIS IS DIFFERENT FROM ALL THE
OTHER GAMES OF ADVENTURE!!!! It is
played on a computer generated map of
Alesia. You lead a small band of adventurers
on a mission to conquer the Citadel of Moor-
lock. You have to build an army and then arm
and feed them by combat, bargaining, explora-
tion of ruins and temples, and outright ban-
ditry. The game takes 2 to 5 hours to play
and is different each time. The TRS-80 Color
version has nice visual effects and sound. Not
available on OSI. This is the most popular
game we have ever published.

32K TRS 80 COLOR Version $24.95.
Adds a second level with dungeons and
more Questing.

PRICE AND AVAILABILITY:

All adventures are $14.95 on tape. Disk
versions are available on VIC/COMMODORE
and TRS-80 Color for $2.00 additional. $2.00
shipping charge on each order.

ALSO FROM AARDVARK - This is only a partial list of what we carry. We have a lot of other games (particularly for the
TRS-80 Color and OSI), business programs, blank tapes and disks and hardware. Send $1.00 for our complete catalog.

r 2352 S. Commerce, Wal

TRS-80 COLOR

TIMEX/SINCLAIR

AARDVARK

$2.00 shipping on each order

led Lake, MI 48088 / (313) 669-3110 £
Phone Orders Accepted 8:00 a.m. to 4:00 p.m. EST. Mon.-Fri. TNT

COMMODORE 64

VIC-20

each program from the first line each time, just load in any
number of subroutines and combine them with your new
"application." Your programming speed will increase many
times over. By "chaining," I mean that a tone could place in
protected memory certain items of data and have this data
shared by many other programs, each being able to change or
modify the contents of the data.

Files and other data structures are supported on this system
with easier manipulation of information. You will not have to
dimension arrays for storing data, worry about RUN or
CLEAR destroying hours or days worth of work, or be
concerned with managing the memory.

You will be able to create animation easily, plot complex
functions directly in high resolution, if desired, and easily
interface your machine language programs with a special
COLORSINS1 system variable which contains the starting
address of your routine. This routine may be located anywhere
in user memory in either a REM statement or a string. The
system software keeps track of its location and automatically
adjusts the variable.

If you should like to obtain additional reading material on
other similar applications and sources of supply for kits and
assembled systems, see the lists at the end of the article.

System Overview

The system consists of a buffered motherboard with six
expansion slots. Two of these slots are designed to accept
Radio Shack boards.

Color with a VDP

Color is produced using the TMS9918A Video Display
Processor from Texas Instruments, hereafter referred to as
the VDP. The VDP has the capacity for producing color
displays and high resolution as well as the ability to create
and manage 32 additional characters called sprites. A sprite is
a variable sized character which may be moved smoothly
over the entire display area in any direction. Each of the 32
sprites has its screen position determined by its own screen
address, so creating animated sequences merely becomes a
series of timed changes to these screen locations.

The VDP also offers four different Modes, each with
varying utility depending on the application. Modes I and II
are graphics modes. Mode I offers up to 15 colors plus
transparent to be displayed on the screen at once. Up to 256
unique characters may be defined. In addition to allowing the
15 colors plus transparent to be displayed at the same time,
Mode II allows all 16 colors to be present in the same
character position. Mode I allows any combination of 8 colors
maximum to be displayed in any one character position.
Mode II offers up to 768 unique characters per display.

Because of the unlimited and unrestricted use of color in
Mode Il, this system utilizes it as the high resolution, 16- color
mode. Mode I, because of its limitation on colors, is used as a
high resolution, 4-color mode.

Mode 1 is sufficient for most appliciations, and allows the
user the advantage of storing up to four pages in memory at a
time, making paging very simple and quick. Mode II displays

Figure 2. The 17 New Commands.

1. REM*DATA;AS;X1,x2...Xn:

A$ is the “name” assigned to a particular set of data. An
unlimited number of data elements may follow, each separated
by a semicolon and the last element followed by a colon.

2. REM*READ A$;X

Reads an element from the data named A$.

3. REM*RESTORE A$

Resets the pointers to begin at the first data element in A$.

4. REM*OPEN N

N is a file name previously defined using the FILENAME
command and limited to an alphanumeric of fewer than 3
characters.

5. REM*CLOSE N

Closes the file and "protects" it from accidental access
during the run of a program.

6. REM*CIRCLE;X;Y;Radius;Color:

A subroutine to draw a high resolution circle anywhere on
the screen with any radius. Any of the 15 available colors may
be used.

7. REM*FILL

Fills the bounded area of the CIRCLE or DRAWTO
command with the same color as indicated.

8. REM*FILENAME X$;

Any three character alphanumeric to “name” a file. As
such, its location can be stored and recalled by name. It may
also be a copied page of the display.

9. REM*VARS A$;

Allows the user to name a variable being used by the Basic
operating system to be used also by COLORSINSI system
commands such as DATA, FILENAME, FIELD, and
SOUNDON. This variable may then be manipulated by a
Sinclair Basic program and instantaneous values used by the
system.

10. REM*FIELD:FILENAME:1 as 2$;2 as 4$;3 as 1$:...X as
Y$:

By using the field command, you can assign specific memory
requirements for each field. In the above example, the first

field uses 2 bytes, the second uses 4 bytes, etc. The record
length is associated to the FILENAME by the system
software.

11. REM*MEMREM

When used in a GOTO statement, may be used to determine
the total number of records which may fit in memory in any
particular file. Uses the information provided by the FIELD
command to make this calculation. The value returned may
be POKEd to place additional files in memory.

12. REM*SOUNDON;channel,pitch,volume;etc.:

The main method of producing the sounds: the available
channels are 1-4, the pitch may vary from 0-1023, and the
volume from 0-15, with the value 15 shutting the tone gen-
erator off. May be used in conjunction with Basic variables
which are manipulated by a program.

13. REM*HRPOS X

When used with a GOTO statement, then the current X,Y
coordinates of character X are returned. Allows the pro-
grammer to determine in software the current location of any
character on the screen.

14. REM*MEMLOC

When run as a GOTO statement, gives an approximation
of the amount of available user Basic RAM space remaining.

15. REM*DRAWTO;X,Y;X,Y;.....X,Y;color:

Connects any two pixel coordinates on the screen. May be
extended by as many destination points as desired without
the final coordinates having to be the same as the first
coordinate. Any of the available 15 colors may be used.

16. REM*BIN

When used in a GOTO statement, calls a special screen
which may be used to define new characters, sprites, or a
high resolution screen.

17. REM*MOVE;FILENAME; origin, destination:

Allows the programmer to move large amounts of infor-
mation around in memory, to or from the protected memory
of the video RAM. Implements the ability to "chain" and
"merge" programs.

July/August 1983 © SYNC

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occupy 12K of video memory, so only one display may be
stored in memory at one time. This mode seems best suited to
games, creating highly detailed images to be dumped to the
printer, and in creating displays where colors may be used
either to form bounderies or to show movement. An example
of this would be in CAD/CAM, where an electronic circuit
could be displayed on the screen, and the pulses on the
circuit shown as changing colors on the line.

Mode III on the COLORSIN81 may best be described as
the multicolor, block mode. All 16 colors may be displayed
on a page, but a combination of four colors maximum may
appear on any one character line. Because of this apparent
problem, the system software will actively support four colors
in this mode. Since the block graphics are very similar to
those of the Sinclair, I have dubbed this the Sinclair mode.

In Modes I, II, and III, sprites and graphics are supported.
Each mode has 32 character positions across and 24 lines
down, the same as the Sinclair. The multicolor mode, Mode
III, has 64 blocks by 48 blocks on the screen, again the same
as the Sinclair. However, Mode IV offers 40 characters per
line with 24 lines down. This mode increases the Sinclair
screen by 25% and makes word processing and other text
related tasks far more readable. Formatting becomes much
easier if you are using an 80-column printer, for you should
not have the problem of broken words. However, with this
feature, you lose the use of sprites, and you are limited to two
colors over the entire screen. However, I am sure that most
of you will enjoy having a larger screen to work with.

In the foregoing discussion of the modes of the VDP, I
mentioned that the system software supported what appeared
to be less than the potential of the VDP. This is because it
seemed sensible to make trade-offs if similar results could be
obtained using one of the other modes. This makes software
implementation much simpler and allows the use of the new
commands (in Figure 2) to make programming much simpler.

However, since all of the functions on this board are
memory-mapped, your are free to use Basic or machine
language routines to create anything you wish. Figure 3
compares the four modes and gives a synopsis of their capa-
bilities.

The COLORSINS1 offers a number of special screens which
may be called as required. These screens will help in defining
your new character set, defining new sprites, or helping
construct a high resolution screen in Mode II. These screens
are interactive in that the user is asked to supply very simple
information and the computer/software takes care of storing
that information in the appropriate memory locations. All
screens and files in this system may be saved on tape, so any

Figure 3. Comparison of the Modes.

Mode

1 2 3 +
Characters/line e s a O32 ee
Lines/screen 24 24 24 24
Number of sprites 35: 3957324 10)
Graphics supported yes yes yes ves
Characters supported yes yes yes yes
Resolution high high block high
Number colors/screen (maximum) 16 16 16 2
Number colors/screen supported E l6 4 2

Maximum number of user defined 256 768 256 256
Characters per screen

July/August 1983 © SYNC

work which you might want to include in another program
may simply be merged with it.

The Sound Chip

Sound is produced with the SN76489A Sound Chip from
Texas Instruments. This IC offers an 8-octave range and 4
separately programmable channels, the fourth being a white
noise generator. Full tone and volume control are accessible.
Programs may be written in either Basic or machine language.
Envelope control allows you to produce complex tones that
simulate the piano or chimes.

The calculated frequency range in this system is approxi-
mately 100-10000 Hz, which should be sufficient for most
applications. The sound is output through an 8 Ohm speaker,
so the sound quality is very good.

The application sheets available from Texas Instruments
create a fairly complex maze of registers and formats which
must be considered when outputting a specific sound. How-
ever, the COLORSINSI software takes care of formatting the
information when the user loads simple, direct items of
information into a command line.

The sound capability has applications in games, in word
processing programs for positive key feedback , and in security
systems as an audible noise source.

The Joystick Interfaces

Two joystick interfaces are provided on board, but up to
four may be active at any one time. These interfaces accept
inexpensve Radio Shack joysticks. The 6-bit resolution is
sufficient to uniquely identify every character position of the
screen. If the joystick is used to manipulate the position of a
sprite, then the sprite may be positioned to the accuracy of a
half character.

This feature is designed for applications in alternative input
mechanisms, in gaming, and in aiding the manipulation of
screen data. When used with the appropriate software, it
could be used to change screen information, to move char-
acters or words from one location to another, or to highlight
an area on the screen.

Additional Options

At the time of this writing, several other options were being
considered for the board: 1) up to 48K RAM on board, in
increments of 16K; 2) a solid state interface to allow the user
to “plug in" programmed PROMs apart from the Sinclair
memory space and load into memory when needed (up to
80K of PROMs could be supported on the system, while using
only 8 memory locations of the Sinclair memory); 3) an
interface which would emulate a disk drive. The principle is
the same as the solid state interface, but would use dynamic
RAMs instead. These new products will become available
over the next several months.

Schematic Overview and Circuit Operation

The motherboard consists of Slot 0, where the Sinclair bus
originates. The address, data, and selected control lines are
buffered by ICs 1-4. The PROMs, P1 and P2, provide all the
address decoding required on the board.

The outputs of the PROM are used to enable ICs 8 and 33,
which are one-of-eight decoders. Inputs A, B, and C provide
binary information which is coded by IC 8 to produce one of
eight active low outputs at one time. On IC 8, input A is
grounded because address line 0 is used as a mode control for
the VDP. The eight outputs (select lines) on IC 33 are
extended to the Radio Shack boards to give the user total
access for interfacing other homebrew boards.

IC 9, sections of which have WR inputs and RD inputs in
addition to the inputs from IC 8, provides the necessary
signals to the sound and joystick sections on the board.

July/August 1983 ° SYNC

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The PROMs allow flexibility in design, in that the relative
addresses of the peripherals on the board could be easily
changed by changing the programming of the PROM. How-
ever, to maintain compatibility with other systems, the PROM
programming should not be changed.

ICs 10 and 11 are latches used to store and continuously
ouput their contents. In the joystick section, the output of the
latch is fed into a CD4050 CMOS buffer. This chip is used
because of its ability to output stable and reproducible voltage
levels on its output. The output of the chip is fed into a
resistor bridge, effectively assigning a “weight” to each of the
data bits.

The sum of these weighted voltages is then fed to the
negative side of IC 22, a voltage comparator. The function of
the comparator is to output a positive voltage if the positive
side of the comparator is greater than the negative side, and
to output a negative voltage when less than the negative side.
The voltage source for the positive side comes from the
joystick itself. The joystick has its own 5 volt supply which
may be varied by the dual potentiometers from 0 to 5.0 volts.
The effective range, after going through a matching circuit of
resistors, is approximately 0.25-4.75 volts. Because we are
feeding 6 bits of data into the section, this 4.5 volts is divided
by 64 equal units of approximately 0.07 volts.

Thus, any change in the position of the joystick creating
greater than a 0.07 volt change could change the position of
the cursor on the screen. However, in practical terms, we are
concerned with character positions on the screen, so the full
precision of the joystick will not be used. However, the
software compensates for this when using sprites as the cursor
by developing trend data in direction and speed to produce
smooth movement instead of the expected jerky movement.

The function of IC 23, a buffer, is to make visible to the
Sinclair via the data bus the present condition of the compar-
ator. The processor, when in the joystick routine, continuously
outputs data to the joystick latch and then reads the joystick
port to sense any change in the outputs of the comparator. A
change indicates that either the X or Y screen coordinate of
the cursor has been determined.

In the sound section, the output of the latch is fed to the
76489A sound chip as data. The sound chip requires that the
data be stable for a minimum of 32 clock cycles at 2 MHz.
Because 2 bytes of data are required to produce a tone, a
maximum of 3200 different tones may be produced per second
using machine language programs.

In Basic, you are not really restricted by the 32 clock cycle
requirement, for it takes a minimum of 1 ms. to execute a
Basic instruction. Therefore, a maximum of 500 tones per
second could be produced. Various frequencies are produced
by rapidly turning the tone generators on and off with a seed
tone varied by time.

The function of ICs 28 and 30 is to divide the 4 MHz
frequency in half to 2 MHz, the maximum frequency the sound
chip can handle. The audio output of the sound chip is fed to
IC 32, an audio amplifier which is used to amplify the tone
and drive an 8 ohm speaker. The large capacitors are used to
improve the bass response of the speaker.

The video section does not use latched data, but receives
its data directly from the data bus. Since the VDP operates
asynchronously, data may be read or written to the VDP
without considering what the VDP may be doing at that
moment. The VDP has its own internal latches to store data
until it is able to act upon it. Because of its high clock rate,
there is no degradation in system throughout. You may run
machine language programs at full speed reading or writing
data without the VDP losing any of it.

The VDP interfaces to the CPU by the data bus, two select
lines, a Mode Control line which is address 0 on the Z80 bus,

July/August 1983 © SYNC

and the reset line from the Z80. On power up, the reset line
resets all registers in the VDP and clears all memory. It is now
in a position to be programmed with data.

Programming is accomplished through the use of the select
lines, the Mode Control line, and the data bus. The Mode
Control line differentiates between VDP register accesses
and video RAM accesses. The CSR and CSW lines, active
low, determine whether the CPU is reading or writing to the
VDP. These signals are used to strobe data into the VDP.
The VDP then performs the required housekeeping duty of
putting the data in the appropriate register or video memory
location.

The VDP also refreshes the dynamic RAMs. The video
RAM side of the VDP uses multiplexed address/data lines to
determine a video RAM address. Two bytes of data are
needed to set the starting address, and one byte of data for
each data word to be read or stored.

The VDP features an autoincrementing register, so that,
once the initial address has been set up, succeeding data
transfers do not need new addresses. At this point, the VDP is
processing the data stream as a parallel port. The 10.73 MHz
crystal may be fine tuned by using the trim capacitor. It is
used to adjust the crystal frequency to match the pixel rate of
your TV. The composite video out signal is fed to an RF
modulator which conditions the signal so that channel 3 or 4
may be used to display the images on your TV. However, if
you wish to drive a color or monochrome monitor, a jack can
be provided.

Constructing and Debugging the Board

This system was designed for incremental construction.
Although the basic price of the system is low, some may
prefer to spread the cost of the system over a period of time.
Certain basic sections of the board must be present for others
to operate, but, once these sections are built, you can extend
the system at your own pace.

The system interfaces to the computer in one of two ways:
1) by a cable running from the expansion port of the cased
computer to slot 0 of the COLORSINS1; or 2) by plugging the
uncased computer directly into slot 0 on the motherboard.

If you have an auxilliary keyboard, you can connect it to
the motherboard using the 25 pin D-type connector on the
board; however, you can do this only if the computer is
plugged into slot 0, for that is the only way to connect the
flex-tail connector of the board to the keyboard input con-
nectors on the computer. You should decide before ordering
what approach you would use to interface the computer to
the system.

Actual construction time of this board will vary from 3-5
hours for the experienced kit builder to 10-20 hours for the
novice kit builder. If you built your own computer, then you
should have no problems. However, even the novice kit
builder, taking his time and following the suggestions in this
article and in the assembly instructions, should be able to
build this system.

Before beginning construction, assemble the basic tools: a
25-40 watt pencil type soldering iron, solderwick, screwdrivers,
a multimeter, and a set of tweezers. The kit building progresses
one section at a time, so you should segregate all the com-
ponements in the kit, arrange them by section, and bag each
section. This will ensure that all the parts you need are
present and will eliminate much searching when you actually
are building the kit.

In general, the basic sequence of inserting parts onto the
board should be: IC sockets, capacitors, resistors, diodes,
followed by other discretes such as potentiometers, variable
capacitors, and transistors. This approach allows you to use
your best judgment in the placement of the components.

July/August 1983 ? SYNC

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The Power Supply

I recommend a 15 volt, 5 amp power supply to acom-
modate future expansion of this system. When fully built with
the computer and a 64K RAM pack attached, the power
consumption approches 2.0 amps at 5 volts. If you intend to
add more than 2-3 boards to the system, you might need to
add a second 5 volt regulator. Although only +5 and +9 volts
are required in this design, the board has room to accom-
modate t 12 volts and -5 volts, obtained using an inexpensive
voltage converter.

By purchasing the proper type of power supply, you will
eliminate much frustration in the future. The power supply
should have a regulated output. (When ordering a kit or
assembled system, inquire about the availability of a power
supply if you need it.)

The Power Regulating Section

The first part of the board to be built is the power regulating
section. This is made up of 3 regulators and heatsinks, 1 IC,
and several resistors, capacitors, and diodes. If you put the
components into groups, assembly will proceed much faster.
Starting with one of the voltage regulators and its associated
parts, assemble the parts to the board and solder using the
component placement layout in Figure 4.

Figure 5 is a schematic of the system and should be used
when debugging the board. You might want to test the power
supply before connecting it to the board. Turn power on to
the supply with no connections to the motherboard. You
should have a voltage of 15-18 volts. After all the components
for the power section have been soldered, attach the power
supply and turn on the power. Referring to Figure 4, locate
appropriate test points and adjust the appropriate variable

s1o93ut.| 1re[outg

potentiometer until the desired voltage is obtained. When
inserting components into the board, pay particular attention
to polarity of the capacitors and diodes. Improper placement
will result in poor performance. Once voltages are set to the
indicated levels, proceed to building the motherboard and
buffers.

The Motherboard

Assemble all the parts for the motherboard and buffer
section. Insert the IC sockets, followed by the connectors
and other components. Carefully inspect your work for solder
bridging, especially on the connectors. For thoroughness,
you might want to check for continuity from one connector
to the next; remember that the address, data, and certain
control lines go through the buffers.

At this point, you have a fully functional motherboard and
may begin using the power of the Sinclair to help in making
the rest of the system operational.

To prove that your computer may help, attach it to the
system, insert some known working board, other than a
memory board, into one of the other slots and turn on the
computer. If the board operates normally, then all aspects of
the motherboard are operating as expected. If the computer
works but the peripheral board does not, then the problem
lies in the soldering of the connectors or IC sockets. If the
computer does not produce a display, then the buffers are not
operating correctly, and again soldering should be checked.

The Address Decode Section

This section is made up of 5 ICs and sockets, assorted
capacitors and resistors. Insert the parts indicated, power the
system up, and check for proper voltages by referring to

Figure 4. Component Layout of COLORSINSI Board.

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PERR pte
A aE
— cH —

System
PROM

Reserved for
on-board RAM

Reserved
for future
expansion

Automatic
Jump
Circuitry

O-Q

July/August 1983 ? SYNC

Why pay more when you can use
your Timex/Sinclair* to tie into a
Available from:

mainframe and/or networks with
DATA-ASSETTE

the COBRA RS 232 56 South 3rd St.
COMMUNICATION INTERFACE. Oxford, PA 19363

$9.95
commen uuu O d 9.9 59

*Suitable for use with TS1000, ZX81 or
Spectrum (Specify when ordering)

COBRA Technology Ltd., 378 Caledonian Rd., Islington, LondonN11DR
Manufacturers of Quality Micro Technology Peripherals

SOFTWARE AVAILABLE
AT

WAT UN DNI CAIRO UE I D PME LR mS SL A EEN OLA SS eee TILER Ly MERE 5, d E IMPR REA QE LU PODER ie, Us ORI re Rene R AS YR Cb

Figure 6. If you have access to an oscilloscope, you can test
this section by POKEing the select addresses as indicated on
the schematic. If not, then you will have to wait until the next
section is added to prove that the address decode section is
operational.

The Joystick Interface

This section is made up of 4 ICs and sockets, capacitors,
component carriers for the resistors and a large assortment of
resistors. Begin by assembling the component carriers as in
Figure 7. Now that 90% of the parts are assembled, you can
concentrate on the sockets and remaining components. Insert
the ICs, power the system up, and check voltages to the ICs.

Once done, enter Listing 1 and RUN it. Check the output
pins on IC1. You should see a rhythmic change in the
measured voltage. If you do not see this activity, then check
your soldering on both the address decode and joystick
sections. If you still are unable to detect the indicated response

©
meg i yE
RESH | Y
RD Eua oy
WR 2] Y
74LS367
]
2 W DIR OE
D7
T 3 ES
an 4 Cm,
D4 : m CR
D3
m» 7 E
DI 8 EA
an 9 Th
5V 74LS245 TE
1K 14
^E TYPICAL
A15 ae E d
A13

OPO ]|][o [oc fab [o hij-

7415245 6301-1J

Figure 5. Schematic for COLORSINSI.

74LS08

to the program, then make a thorough check with a continuity
tester. Check each line in the two sections to verify that no
shorts exist.

Finally, if no problems are detected, then try one of two
other approaches: 1) contact a friend who has a logic probe
or an oscilloscope and ask for assistance in finding the
problem; or 2) purchase additional parts from a supplier such
as Radio Shack to isolate the problem. Although no one ever
likes to admit it, occasionally component failure is the cause
when a project does not work.

After you are able to observe the desired response to the
program, insert ICs 22-24 and the component carriers as in
Figure 4. Power the system and enter Listing 2. If you have
purchased a Radio Shack joystick, assemble it as in Figure 8.
Connect the joystick and RUN the program.

You should be able to place the cursor in each of the four
corners of the display. Do not be alarmed at the response of
the joystick. The machine language program will run many

| |
3
—LDB[» 745257 4[ s

741800

Br dios E 3^
T
muet B Bl
DO
13
Al 1 [15

RESET

4
De
5

74LS00

74LS
74LS02 28

DATA bus

—

=Ni- jov A a oN jojojo

74LS138

RESET
]
39 | XTAL2 36
DF eo
joies 10.7 MHz|
33pf 33pf
42 July/August 1983 ? SYNC

times faster than this Basic program. As the cursor position is
changed from corner to corner, you might take a voltage
reading at pins 1 and 2 of the voltage comparator, IC 22. You
will see the maximum voltages that may be outputted to the
two sides of the comparator.

Sound Section

Assemble the parts for this section and solder. You should
have 4 ICs and sockets, a crystal, resistors, a variable resistor,
2 large capacitors, and a number of small capacitors. Do not
insert IC 32 yet, as you do not want to output a load without a
speaker attached. However, if you want to connect the
speaker at this time, you can leave it in.

Enter Listing 1 again, changing line 40 to POKE 14344. Run
the program to again observe the rhythmic changing of the
voltage levels, particularly on pin 2 of IC 10. Do not be
concerned with the hiss that you might hear from the speaker.
The sound chip occasionally outputs a sound on power up.

ROM
CS

RAM
CS

+ CD4050

+ 5V CCIA,B E
: i

E i
E
ig, u23 D5
u24 m
3 id 7415367
E
Bi
5V
2.7K DATA bus
ae ee 3
72 Bp.

u30
3

74LS74

O -NUAR UO N

NM TOI fo [to [01 To
Oo [-— JN Jo [C N

0. luf
10 Ohms

0.0: 0° uuu.

out 7

u31 B
6
h

SN76489A ^ 10K

10 pf 10K

14 14 14 14 14 14 14 14
2 Q 2 pÊ 2 DQ 2 2 p9 2 2 DQ
BERE. S
sary By SET mu
i 2 5 be SEY
? f
EE Loo L:-51 RF wed L. 6 [1:67
SRE Beet
4116 4116 4116 4116 4116 4116 4116 4116
To
color
or b/w TV

100 Ohms

= . uMI082

July/August 1983 * SYNC

You can reduce the volume by adjusting the variable resistor.

Enter the program in Listing 3 and RUN it. You should
hear a series of tones which sound like a chime. Adjust the
variable resistor until succeeding runs of the program produce
the tone at the desired volume level. Now proceed to the next
section.

Figure 6. Power Connections.

IC P/N GRD +5 +9
L23 74LS245 10 20
4,23 74LS367 8 16
5,6 6300-1J 8 16
7 74LS08 7 14
8,33 74LS138 8 16_-
9 74LS02 7 14
10,11 74LS373 10 20
12 TMS9918A 12 33
14 74LSO8 14 2;
15 D 2716 12 24
16, 30 74LS74 T 14
17 74LSOO 7 14
18,19 74LS257 8 16
22 LM339 12 3
24 CD4050 8 Í
28 74LS04 7 14
31 76489A 8 16
32 LM386 4 6 [+12 -5
34,41 4116-150 16 9 8 l
Figure 7.
1 261 K 100 K 10 K
2 147 K 51K 10 MEG
3 75 K SK 1K
4 38K 13 K 10K
5 19 K 5K 10 MEG
6 10K 2.6 K 1K
7 100 K 1K 20 pf
CCIA CCIB CC2A,B

Insert the resistors and capacitors into the component carriers as shown. Resistors
in CC1A, B are 1% resistors. CC2A, B have 5% resistors.

Figure 8.lJoystick.. — =- Se

Assemble the Radio Shack joystick as shown. You should get a dual 100K
joystick.

Listing 1. Latch test.

1o SLOW SOC FORE

Listing 2. Cursor test.

20 LET Z=14350 40 POKE ZI s we ban
E, UE 10 SLOW
20 LET Z=14350
Vileo and Video RAM hs Seis i - 1 Mus Mar
This is undoubtedly the section many of you have been SO IF PEER Z-128 THEN GOTO 150
waiting to get to. 60 IF PEEK Z-192 THEN GOTO 200
This section consists of 3 ICs and sockets, an RF Modulator RO CENE
and/or a monitor jack, a variable capacitor, a crystal, and ELT. UAR
several resistors and capacitors. Insert and solder all the 100 IF PEEK Z=64 THEN GOTO 170
components as in Figure 4. 110 NEXT 1
Enter the program in Listing 4 and RUN. This program deis et ne
loads data into memory locations in video RAM and then (9 det T
reads these same locations and prints the results. You will 18O PRINT AT X/8,Y/4; CHR$128
notice that the program increments the data in multiples of 2; RM Ho pe *
if, when printing the information to the screen, you notice a Ea
zero appearing where a number should be, this can aid you in 210 LET YeX
determining that you might have a bad solder point in the 220 GOTO 180
section. It will even help to identify which line might be bad

in that each bit of data has its own pin on the RAM chips that
it enters and exits. If the demonstration program does not
operate as expected, again check soldering quality and con-

Listing 3. Chime demonstration.

tinuity. When the section works, you are ready to add the 10 FAST

PROM interface and the automatic jump circuitry. UB A POLES a Sh
This section will be revised later to make use of the new 4416 ai dies sab bs base UD dt

memory chips from Texas Instruments when they become 40 ROKE Z, 191

available. The required chips will be reduced from eight to d: X poen

two. This offers many advantages to the kit builder and user ic HEM deer Smee

because debugging is much simpler and system reliability is
increased. These chips could also be used whenever the on- 75

board memory option is added and whenever possible in other bx
suitable applications. 100
Figure 9. Switch Settings. a

012.34 5578 130

1 = On ihe

A obor roo 1 150

12.5456 7 8

00000000

Set the switch as in A to cause an automatic jump to the system PROM.
Use the settings in B when running unmodified Sinclair programs.

PROM Interface and Automatic Jump Circuitry
The PROM interface consists of 1 IC and socket. Insert

and solder and check for proper voltage levels. The Automatic E
Jump circuitry consists of 4 ICs and sockets, an 8-position is
switch, 2 transistors, and 2 resistors. Insert the components, TE

solder and check for proper voltage levels.
You might notice that you no longer have a cursor on the
display. This is expected and normal. If the PROM was

iO POKE

220 GOTO
e EE ER RN LES SCE 5 ae ERE MEE [IE iy ute 1^ Det S COE SCR

INPUT A$
REM ENABLE
PORE 140
FOKE Z, 5
POKE Z, 170
FORE Z, 5
REM NUMBER OF BELLS

THE OUTPUTS

rA
=
4,

FOR Reo TO 11
FOR Isi145 TO 159

Eu
Z, (1+32)

FOKE

( REM DELAY

FOR D-o TO 1
NEXT D

NEXT I

NEXT R

Listing 4. VDP and memory verification.

LET

2 FAST

LET WR=14349
LET RWR=14549

LET RRD-14346

REM SET UF STARTING ADDRESS
FOKE WR, ©

FOKE WR, 44

inserted, the computer is now executing instructions in this QO REM ENTER DATA
PROM and is waiting for you to input something through the 90 LET Z=Z+1
keyboard 100 FOR I-1 TO 50
A t10 LET Z-Z*2

At this point, you might want to disconnect the TV cable
from the Sinclair and attach it to the RF modulator on the

PORE RW, Z

NEXT I

motherboard. Set the switch positions as in Figure 9 and : T Pecan gd HOTA
66 * $00 PURE WR, ©
power the system up. The prompt "READY" should appear 160 POKE WRO
on the screen. At this point you have a fully operational 70: LET. 94
system ready for you to develop applications. ue "E ie.
° ° ic Ube i-—: 1:50
If you have a video monitor, or another TV, you may want lad bp
to connect one to the computer and one to the motherboard. 200 PRINT PEEK (RRD);
In this way you can see what is happening to the Sinclair 210 PRI x CHRO 5
220 NEXT Z
display. 230 PRINT "DONE"

When running application programs which have not been
converted to run on this system, set the switch positions as in
Figure 8, power the system up, and observe the results of the

Try varying the numbers in lines 140 and 180. Observe the effects.

July/August 1983 ° SYNC

^ - e
AŽ ^ 7
. DNE Du

ventüre gam
SINCLAIR

COMMODORE
ZX 8l

VIC 20
AGK RAM)

only $]4.95

CALL (313) 565—3586

Ere er ee ee paf wd nou uncle e sa rer qe

CHARGE TO Please rush me.
[^ check or money ordér $14.95

į Payable to BMS

l 51-23

ED eo 5 add

game — sales | F

ix E

i ADDRES SHIPPING 1.50 |

b iw. oe CDD
to: B.M.S. PO. BOX 4073, DEARBORN MI. 48126 _

MPa ETT c EE E REED A Fy he a E i ie eA a NND IS SUCCO apre A ed er LIU" UPS Calle MUS 9 UEM LR

program through the Sinclair TV display port. If the sound or
joystick features are to be used, then at some point early in
the program LET Z — USR x, where x represents the
beginning of the PROM subroutines for these features.

Programming the System

The joysticks are enabled in this system by POKEing six
memory locations. The first location tells the software how
many joysticks are to be active during this time period, and
the second location actually enables the joysticks. Up to four
joysticks are supported by the software. The next four loca-
tions are used to store the code number of the character to be
used as the cursor for each joystick. If you wish to use sprites
to indicate the position of the cursor, then zeros should be
POKEd into these locations. The software will automatically
use the four highest priority sprites as cursors.

The sound features are implemented by the SOUNDON
command. The three parameters in the command are used to
choose the desired tone generator, the pitch to determine the
frequency, and the volume which is used not only to vary the
volume, but also to turn a tone generator off. You can use
variables for any of these parameters so long as they have
been declared previously by the command VARS. You may
also add multiples of these three parameters in the same
REM line if you wish, the only condition being that separate
groups be separated by semicolons and that a colon follow
the last parameter in the REM line.

Most of the other commands are self-explanatory, and a bit
of experimenting will quickly enable the programmer to
produce application programs far easier than ever before and
in much less time.

For those who purchase a kit or an assembled system, the
accompanying manuals will detail in far greater depth how to

program the system and develop applications. Sample pro-
grams and applications will be included to help encourage
the new owner to discover the true power of this system as
compared to the unmodified Sinclair.

Conclusion

I am sure that many of you are looking forward to using
your new Sinclair. You should! You now have one of the
most powerful computers on the market for under $1000.
You have the superior graphic capability of the Texas Instru-
ments 99/A computer, the high resolution of the Apple, the
easy editing of the TRS-80, and sound comparable to the best
on the market. You have the advantages of easy expandibility
and interfacing, of adding new utilities on PROM to further
expand the capabilities of the system, of adding new RAM to
the system inexpensively, and of connecting your keyboard,
if you have one, to the system. Best of all, you have the
advantage of being able to expand your system at will from
the large selection of inexpensive Sinclair peripheral equip-
ment on the market.

I am sure that many of you are indecisive about investing in
this type of expansion because a "better" computer might
become available, or because this is your first computer and
later you might decide to get another. Well, this system is port-
able. It may technically connect directly to any Z80 based
computer such as the TRS-80. You might not be able to use
the PROM designed to work with the Sinclair, but adding
several routines to accommodate the TRS-80 should not
be at all that difficult. Also, since most of the Z80 signals
are duplicated in some manner on other microcomputers on
the market, interfacing should be relatively simple. So not
only are you investing in your Sinclair for today, but also you
are looking forward to extending the capabilities of your
future system.

LIMITLESS EXPANSION FOR SINCLAIR/TIMEX

FLOPPY DISC INTERFACE $179 +1-4 DRIVES, ANY SIZE * SINGLE/ DOUBLE
DENSITY * INDUSTRY STANDARD IBM FORMAT * ON BOARD DOS IN ROM "
RIBBON CABLE CONNECTIONS FOR MAXIMUM RELIABILITY x

1000 TIMES FASTER THAN CASSETTE

9.20 DOUBLE DENSITY FLOPPY DISC DRIVES $189 za.

POWER AND CABLES FOR 2 DRIVES $79
STD BUS INTERFACE $99 COMPLETE WITH RIBBON CABLE

CHOOSE FROM 300 PERIPHERAL INTERFACES, 60 MANUFACTURERS

CENTRONICS PRINTER INTERFACE $119 compete wirH *

PRINTER CABLE, SOFTWARE IN ROM

DIRECT VIDEO MODIFICATION $25 we iwsraLL $15vou INSTALL
WORD PROCESSING SOFTWARE PACKAGE $15 MACHINE LANGUAGE

i R*eàs.

BOX

(512)

18093 AUSTIN

TX 78760-8093
385-7405

July/August 1983 * SYNC

FULLER MICRO SYSTEMS ADD STYLE, POWER, VERSATILITY

AND FULL TYPEWRITER KEYBOARD OPERATION TO THE
AMAZING ZX81 COMPUTER! WN

THE FULLER FD42 SYSTEM
The ideal Christmas Gift for
ZX81 user. — MN oV o

If you already are the proud owner of the fastest selling small computer in X » NEN p riga
the U.S., or maybe have a friend or member of the family who's a ZX \ Bee a

fanatic, what better buy is there this Christmas than the famous Fuller FD42 % TU ae
System! It converts your ZX81 into a sturdy, attractive and professional unit, gui

with full sized typewriter keyboard. All the Sinclair
ZX81 keys are duplicated with extra shift and
new line keys. The professional momentary

action key switches have a guaranteed life

of 10? operations, and the whole unit
comes to you complete with a money
back guarantee.

IT'S EVEN CHEAPER IN
KIT FORM!

FD 42 keyboard and case kit.

6 £90? T $6 p & p.
FD 42 keyboard kit

AmTurn your ZX81
from this to this

$37??.sapa&p. 1 lOr.. j
J FULLER MEMORY EXPANSION
IT S SO Fw a mosse Hoo ba Cpu eda
e basic 1 has only 1k of RAM - now you can
TO INSTALL. add on an enormous 16 or 64k with our FD Memory
You simply unscrew the ZX Modules. 4 95
printed circuit board from FD16k ;
E bs base, p it into the + $4 p&p.
cert the new FD case, and 95
a. G plug in the keyboard. No FD16kto fit inside Fuller case $59
Ems Soldering or technical t $4 p & p.
knowledge required. S$ 95
FD64k Memory Module____ 1 29

ZX81 MOTHERBOARD dac re eu Qu

Also easy to install! The FD system Motherboard fits
inside the Fuller case and allows expansion to the ZX

memory and 1/0 facilities
DR EEE See A LON IB Mem os os $30.95 T $4 p&p.
3 slot $39.95 +$4 p&p.

NEW! — Programmable Sound
Generator - adds exciting new

Please supply the following items:

sounds to the ZX81 range $39% + sapeap.
Separate P.S.U. 9 volts @ 2 amps $14.9 +$4 p&p.
Plug Planner- complete with 3 metres e

of cable and power jack 306?5 .s6p& p.

Ram Adaptor Board - adapts Sinclair RAM
pack to fit inside Fuller case

$19 4s4 pap.

MICRO
SYSTEMS

^ Mail to FULLER MICRO SYSTEMS,
The ZX Centre, Sweeting Street, Liverpool 2.
England U.K.

g Pip uo VIL CN ERES iS
Edirpieh i oe sca edi eo P EE EAD
City/State ID e. aks Sas

+ US Dollars SY.7.83
an | i BM M NM BM BM BM eG gl

Mail to: FULL MICRO SYSTEMS,
The ZX Centre, Sweeting Street, Liverpool 2.
England U.K. Telephone: 051-236 6109

Wu dw eec Mee du LEM LII UN LE I V eI EM NK RI I eK AI PEEL ADM ae

References

I wish to acknowledge my indebtedness to the following
authors and publishers for their kind permission to use
concepts from their work in developing this project:

"Add Programmable Sound Effects to Your Computer," by
Steve Ciarcia, Byte, July 1982, McGraw-Hill Publishers.

"Build a Joystick A-to-D Converter for Your TRS-80 Model
III,” by William Barden, Byte, January 1982, McGraw-Hill
Publishers. Used by courtesy of Howard W. Sams & Co., Inc.

"High Resolution Sprite-Oriented Color Graphics," by Steve
Ciarcia, Byte, August 1982, McGraw-Hill Publications.

“A Guide to Using the Texas Instruments SN76489A Sound
Generator," by Ted Mahler, Texas Instruments Application
Report. Courtesy of Texas Instruments Incorporated.

"Advanced Circuits, SN 76489A," November 1981. Courtesy
of Texas Instruments Incorporated.

“TMS9918A/9928/9929 Video Display Processor," 1981.
Courtesy of Texas Instruments Incorporated.

For reprints of the articles appearing in Byte Magazine,
write to: Byte Publications, 90 Main St., Peterborough, NH.

For further information or technical literature from Texas
Instruments, write to: Texas Instruments Incorporated, Cus-
tomer Response Center (1-214-995-6611). When requesting
information, be as specific as possible and mention this article
for best results.

Suppliers and Technical Information

The parts for this project may be ordered from:

Daniel G. Roy, 99 Andover St., Lawrence, MA 01843. 1-
617-682-5132; 6:00-7:00 p.m. |

CAI Instruments, PO Box 2032, Midland, MI 48640. 1-517-
687-7343; orders: 9 a.m. to 4 p.m.; technical information 6-7
p.m.

Following is the parts list. Enquire concerning assembled

price, power supply, and any options desired.

Complete kit of parts (PC board, documentation, PROM,
and all necessary parts, less power supply): $159.95.

PC board, PROM, documentation: $59.95.

Connector, address decode, and buffers: $29.95.

Video: $49.95.

Joystick interfaces: $9.95.

Sound: $14.95.

Automatic jump circuitry: $4.95.

Parts List

Power Regulating Circuits

U29 LM350
U25 LM317
U26 7812
U27 ICL7660

1 +5 volts, 3 amps.

1
0.1 uf capacitor 2

+9 volts, 1 amp.
+12 volts, 1 amp.
—5 volts, .1 amp.

10.0 uf capacitor

1.0 uf capacitor
tant

1N4004 3

240 Ohm resistor 2
5%

TO-220 heat 3
sinks

socket, 8 pin 1

5K variable 2
resistor

diode

Motherboard, line buffer, and address decode circuitry

UL23. 14LS245 3 line buffers, bidirectional
U4 74LS367 1 line buffer
U5,6 6300-1J 2 2564 programmed proms
U7 74LS08 1 2 input AND gate
U8,33 74LS138 2 3-to-8 decoder
U9 74LS02 1 2 input NOR gate
U28 74LS04 1 hex inverter
R1-R8 8 1K, 5% resistors
PO-P4 5 Sinclair 46 pin connectors
P5-P6 2 Radio Shack 44 pin connectors
11 assorted 14,16,20 pin sockets
Sound Circuitry
U10 74LS373 1 8 bit latch with output enable
U31 76489A 1 TI sound chip
U30 74LS74 1 dual D-type flip flop
U32 LM 386 1 0.4 watt audio amplifier
4,000 MHz |] crystal
1 1.0K, 5% resistor
1 2.2K, 5% resistor
1 10.0K, 5% resistor
1 2.7K, 5% resistor
1 10.0K, variable resistor
1 0.1 pf capacitor
2 250 uf capacitor, 25 volts
1 10.0 uf capacitor, electrolytic
4 assorted 8,14,16 pin sockets
Joystick Circuitry
U11 74LS373 ] 8 bit latch with output enable
U24 CD4050 1 CMOS buffer
CC1A,B 2 component carriers (see Figure 7)
CC2A,B 2 component carriers (see Figure 7)
U22 LM339 1 dual comparator
U23 74LS367 1 buffer
8 assorted 8,14,16 pin sockets
2 dual 100K Ohm Radio Shack
joysticks
4 component carriers, 16 pin
Video Circuitry
U12 TMS9918A 1 TI VDP
U34-41 4116-150 8 4116 RAM chips, 16K x 1,
150ns.
10.7386 MHz 1 VDP crystal
2 33 pf capacitors
VCl ] 9-35 variable capacitor
1 1K variable resistor
1 100 Ohm 5% resistor
Um 1082 1 RF modulator
] video monitor jack (optional)
9 assorted 16,40 pin sockets

Prom and Automatic Jump Circuitry

2K X 8 bit prom, 5 volts only
U16 74LS74 dual D-type flip flop
U17 74LS00 2 input NAND gate

U15 D2716 1
1
1
U18,19 74LS257 2 2 to 1 multiplexors
1
6

SW 1 8 position dip switch
assorted 14,16,24 pin sockets

*also required, 49 pc. 0.01 uf decoupling capacitors

"s
July/August 1983 © SYNC

Bü sinciai- 1000 |

„eas Squares Analysis

s Prosraitimiho:

— - * Alternative Display
. © Storing Words

Space Warp

Graphics Game

M ARCCOS ARCTAN
cd CLEAR — CONT

EXP

or any other Sinclair computer,

you've probably discovered that
the big microcomputer magazines
cover only the bigger computers.
Where can you find helpful articles on
the Sinclair? In Sync!

Sync is the one magazine that's
written exclusively about Clive Sin-
clairs marvelous inventions, the Sin-
clair computers. And it's the one
magazine to read if you want to get
more from your Sinclair.

You'll find program listings for
games, helpful programming tech-
niques, hardware upgrades, math and
science programs, news of new prod-
ucts for the Sinclair—in short, every-
thing you need to use and enjoy your
Sinclair to the fullest.

In just two recent issues, for exam-
ple, we covered:

L] Putting a Reverse Character in a

String
L1 How to Double Your Memory
O Least Squares Data Analysis With

. the ZX80/81
L] Space Warp: A Graphics Space

Game

L] How to Reduce "Blank Screen

d you own a Timex Sinclair, a ZX81,

NO | "SOR c MAE
IN
AT Pew IN KEYS 9

PEINT

CHAS
LOAD

NOT

O Storing Three-Letter Words in an
Array

O Software Review: ZX Galaxians

O An Introduction to Expression Eval-
uation

O Short Programs Just for Fun

[] The ZX81 Parser and User-Defined
Commands

O Understanding Floating Point Arith-
metic

O Handling Strings from Another Di-
mension

O Book Review: Understanding Your
ZX81 ROM

[] How to Add a Keyboard to Your Sin-
clair

O Translating Other Basics: DEF on
the ZX81

L] Six Outer Space Games—With Pro-
gram Listings

L] Hardware Review: Sinclair ZX Spec-
trum High Resolution Color /Sound
Computer
If you own a Sinclair microcom-

puter, Sync is the only computer mag-

azine you really need. Subscribe now

to Sync, and you can save up to 33%!

Just complete and return the post-

age-paid reply card or the coupon

at right.

SINCLAIR

AND
TIMEX

SINCLAIR

SAVE UP TO 33%
ON SYNC!

— Irc
CN 1986 : Morristown, NJ 07960
YES! Please send me
Sync for:

One year (6 issues) for $12.97—
| save 19%.

[]

O Two years (12 issues) for $22.97—
| save 28%.

Three years (18 issues) for
$31.97—1 save 33%.

Savings based on full 1-year subscription price
of $16.

(please print fuli name)

Address. .— . "nee cae INDE C

4815

State — o a

CHECK ONE:
O Payment enclosed. UO Bill me later.

Offer valid in U.S. and possessions only. Please allow
60 to 90 days for delivery of first issue.

Connect a Monitor to the TS1000 cass 5. Lewart

Using a Timex/Sinclair 1000 with a
video monitor instead of a TV set gives a
dramatic improvement in the picture
quality. This is particularly so with respect
to the TS1000 graphic symbols.

Although the computer comes only
with a standard RF output, it is com-
paratively easy to provide an additional
monitor output. My modification requires
only a single transistor: a Radio Shack
2776-2009 or equivalent. No traces have to
be cut on the TS1000 board. The result is
a display with full brightness and contrast
on any run-of-the-mill monitor. The mod-
ification should take no more than 10
minutes to perform.

To perform the operation, first remove
the Phillips screws on the bottom of the
computer (some of these screws are hid-

Cass R. Lewart, 12 Georjean Dr., Holmdel, NJ
07733.

IT'S SO EASY

To expand your computer when you have
the Solutions

Figure 1.
TS1000 bottom view
(not to scale)
RF modulator

Expansion edge
connector

Remove

To tape
recorder

den under the rubber feet). Then make
the soldered connections as shown in
Figure 1. Tap the video input to the RF
modulator and use one of the other two
inputs as power supply (B+) for the tran-
sistor. To get B+ on the lead indicated,
the computer channel switch must be kept
in the Channel 2 position.

The video voltage at the input to the
RF modulator is approximately 1 Volt

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peak to peak. This would be sufficient to
drive a monitor with sufficient contrast
and brightness. However, the source
impedance at this point is nearly 1000
Ohms. Therefore, a direct connection to
a 50-75 Ohm monitor means a voltage
drop to less than 100 mV. The result
would be marginal brightness and con-
trast. The NPN transistor connected in
the emitter follower configuration, as
shown, provides the required impedance
transformation, so that the full 1 Volt
peak to peak reaches the monitor inde-
pendent of the impedance of the
monitor.

Next, decide where to mount the video
monitor output jack. You can mount it
next to the RF output, or, if you are not
planning to use the RF output, you can
use the RF jack and bypass the RF modu-
lator. My own solution, though not a very
neat one, was to let two wires dangle
through one of the holes and to connect
the wires to the monitor with clip leads.

"n
July/August 1983 ° SYNC

LTEXT AND ZTEXT -+ ZX COMPENDIUM Vo
ZX81 WOR D P H OCESSORS , eg 4 : i Mor | e a [Am OF PLAY. ly

e ALL LEGAL CHESS MOVES INCL.

lower case characters | " PENES nn EN PASSANT, CASTELLING & PAWN TO
; / QUEEN PROMOTION.

on the ZX printer !! ig as e ON SCREEN BOARD DISPLAY.
M TR e SIDES CAN BE EXCHANGED AT
ANY TIME.
e SET UP FROM ANY POSITION.
e OPENING MOVE LIBRARY.
e VERY HIGH STANDARD OF PLAY USING
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e RESIGNATION AT ANY STAGE
e PROFESSIONAL PACKAGING &
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3D TIC-TAC-TOE.
e ON SCREEN DISPLAY OF CUBE NET.
e 64 POSSIBLE WINNING LINES.
BOTH CASSETTES | ° VIRTUALLY IMPOSSIBLE TO BEAT.

ALL FOUR FOR THE 16K NIM.

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commercial machine. ZTEXT (upper case characters only) and GAME ‘MASTERMIND.’
POSTAGE. LTEXT (not so fast but upper and lower case characters) are word POSTAGE. e RANDOM CODE GENERATOR.
processors which incorporate a text editor and a formatter/ printer. e NEVER GETS BORED OF MARKING.

The text editor allows you to type in and edit it. The formatter/printer ORDERS AND OASIS SOFTWARE

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embedded in the text. Included in the range of commands are such useful operations, as string search, ENQUIRIES TO LOWER NORTH STREET. ARGUABLY THE MOST
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utilising the high resolution graphics feature of the ZX printer Graham Asher has built a complete set of
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Asteroids, Centipede,
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Fantastic Action & Graphics

DK KEYBOARD
$89.95

Full Size - Full Stroke 52 Keys (Includes 12 Key Numerical Pad)
Attractive Black Leather Grain Case Holds your Sinclair PCB & Memory Inside
43 Key With 2 Color ZX Legends Simple Installation

Measures 15x6x3 i d

Simple Plug-In Installation to Sinclair PCB cran anid d pad ese bis

One Key Selection of Function, Graphics & Shift Lock Mode

Two LED Mode Indicators

Extra Wide Shift, Enter Print and Space Keys — Speed Pro-

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GRAPHICS SEIKOSHA 6 P 100

Printer Package
ROM B
" HD $369.95

$ 49 5 9 5 Featuring the Super Board
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RS 232 & Centronics
on Board Ram To Order Please Send Check or Money Order.
Eprom Read Board Please Add $5.00 Shipping and Handling.

Requires 3 Solder Connections

Adding A Joystick
To The Timex-Sinclair 1000 James w. Stephens

Most active graphics programs for the
TS1000/ZX81 use the unshifted cursor
keys to control movement. Even though
you can struggle your way through the
program, this type of control is much like
trying to drive an automobile using only a
keyboard. It is just not natural.

After running my flight simulation pro-
gram for a few days, I decided that I
could probably improve my sloppy land-
ings if I had a control stick.

Figure 1. Printed circuit board.

JUMPER THIS CENTER
LAND TO KB4 - SOLDER

The Atari Controller

My son's Atari controller's plug fitted
perfectly into the 15-pin RS232 connector
that I used for my full-sized keyboard.
Since the Atari stick is just a four-position
switch, it seemed that a little rewiring to
the connector would be all that was
required.

However, when I checked the Atari
plug with an ohmeter, I discovered that
several of the contacts were wired with a
common line. The controller would have

James W. Stephens, 2324 Dennywood Dr., Nash-
ville, TN 37214.

Figure 2. Cable connector to ZX81. ———

FRONT VIEW

MINIATURE CONNECTOR
MALE-AMPHENOL SIZE 25
OR SIMILAR

to be rewired. As a result, it could no
longer be used with the Atari VCS. So I
went to our local Atari distributor and
found that he had joysticks in stock for
only $8.50.

Figure 3. End view of Atari plug.

KB1 =D

KB3 KB4 D1 KB2

The controls of the stick are simple
indent type buttons on a printed circuit
board. The diagram in Figure 1 shows
how these are mounted on the board.
The movement of the stick pushes plastic
fingers down to close either one or two of
these contacts at a time. When I com-
pared the circuit to those of the ZX81
cursor controls, I found that only one of
the copper foils had to be cut and jump-
ered. This rewiring is as shown in Figure
1

Converting the Atari Controller

All that is required to convert the con-
troller is to cut gently the copper foil on
the circuit board as shown in Figure 1
and jumper this switch connection over
to the edge marked KB4. However, the
proper connections must be made at the
15-pin connector as shown in Figure 2.
The connector is then hard-wired into
the ZX81 printed circuit board as shown
in Figure4. The male connector is wired
directly to the original keyboard socket

— Figure 4. Printed circuit side of ZX81 board. _

SOLDER POINTS FOR KEYBOARD SOCKETS

D D KB KB’ KB KB KB
Cul E d RV Nhe:

connections by a short length of ribbon
cable. This connector can be mounted
into the top right-hand side of the case
for good access.

Use great care when soldering to the
socket pins since you will be very near
small diodes which are sensitive to heat.
Pre-tin your ribbon cable leads and solder
bridges. Even though you do not need all
the connections for the joystick, it is a
good idea to wire all of the connections
now since you may want to add a full-size
keyboard later.

Guard against possible static discharge
when handling the bare circuit board of

July/August 1983 ? SYNC

e Powerful - fully programmable 2K memory * Portable
- 65" x 6%” x 1%” - 12 oz. e Expandable - Optional 16K
RAM module eSingle-key entry commands
e Educational *« Unique syntax-check report codes for
error identity e Accurate to 912 decimal places for full
range math and scientific functions ° Graph drawing
and animated display * Advanced 4-chip design
combining power, portability and affordable price.
TS1000 INCLUDES: Computer, power adapter,
leads/plugs for connection to TV & cassette recorder,
TV/computer switch, full instructions, and computing

course manual.
T951000 ......... . $69.95

DS TIARA

TIMEX

A E DNE

ACCESSORIES FOR HIGA =inciair 11000 and ZX81

TS1016 - Expands TS1000 from 2K to 16K of memory. (5 oz.) . $49.95

Keyboard Mask for Your
ZX81/1000* sailed’

FEATURES:
e Install in seconds. Remove

JE682-AK KEYBOARD
KIT MOUNTED IN DTE-
AK ENCLOSURE. LIGHT
TAN PANELS WITH
MOLDED DARK BROWN
END PIECES. SIZE:
14% "W x 3%2"D x 3%2"H

TS2040 - 32 Column thermal printer for TS1000 and ZX81 . . .

. $99.95

ZX81/1000* Keyboard
Conversion Kit

adhesive backing from mask
and place over keyboard.

e All characters and symbols
reproduced on mask.

e Durable — formed with poly-
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62636363
FETTE TRAE

JE681 KEYBOARD MASK

The JE682 Kit provides users of the ZX81/1000 series computers a full-size in-
dustrial keyboard hook-up to their computer. The JE682 Kit allows the use of
either the full-size keyboard or the Sinclair/Timex Keyboard. The Kit also per-
mits the simple disconnection of the Sinclair/Timex Keyboard for portable
use. The JE682 Kit consists of a full-size industrial grade keyboard with 62
keys, 2 p.c. boards, 18" ribbon cable, DIP socket and 4 rubber feet. The
keyboard conversion kit can easily be mounted into the DTE-AK enclosure.
This enclosure is large enough to contain the ZX81/1000 computer and the
A handy label representing the ZX81/1000

The JE681 Keyboard Mask provides users of the
ZX81/1000 series computer the individual feel of

full-size keyboard together.
keyboard layout is placed on the enclosure.

each keypad on the keyboard. The mask has a rais- JE682-AK Keyboard Conversion Kit...... $99.95 ea.
ed outline around each keypad allowing the user to (WITH DTE-AK CASE - AS PICTURED)

feel and correctly position their fingers onto the | JE682 Keyboard Conversion Kit......... $59.95 ea.
keyboard. (WITHOUT DTE-AK CASE)

JE681 KEYBOARD MASK ..... $9.95 each DIE-AK CASE ONLY s s Lord ez s $49.95 each

*ZX81/1000 is a trademark of Sinclair/Timex

BREESE BiS Simcissir SOFTWARE | EEE EE

THE ORGANIZER

An information storage program. Store the names, addresses,

ALL TIMEX SINCLAIR SOFTWARE AND TIMEWORKS SOFTWARE REQUIRE 16K OF MEMORY

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phone numbers, birthday and anniversary dates of your friends
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This program constructs, generates, and calculates large tables
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A personal or business checking account program to store and
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Send S.A.S.E. for Monthly Sales Flyer!

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Realistic deep space adventure to save Earth. You, the Captain of the Starship Columbia, attempt
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PartNo: TA ie oats tae WES o EN doe

Spec Sheets — 30¢ each

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Take control of highly maneuverable light aircraft. With controls,
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Part No. 033002 ............. $19.95

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Navigate your way through a three-dimensional maze, with trap-
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Part No. 034006 ............. $14.95

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Plays like the arcade game. Hop the frog over traffic, snakes,
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Part No. 034012 ............. $17.95

Drill yourself on addition, subtraction, multiplication, and divi-
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Part No.033000........... $14.95

Finally!

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* Word Processing *

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WORKS IN 16K to 64K!
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ONLY $13.95 Order: N64K
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ABLE:

FOR YOUR BUSINESS:

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IOPERATION FOR QUICKNESS. WRITE,
EDIT, DISPLAY, SAVE OR LPRINT
YOUR TEXT. SPECIFY 16K, 32K, 48K OR
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2. TEXT FORM — USE YOUR KEY-
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THAN TP SERIES (SEE 1 ABOVE) BUT
YOU CAN "RUN" THE PROGRAM AND
NOT LOOSE YOUR TEXT. 16K, 32K, 48K
AND 64K “RAM” VERSIONS.

3. CHECKS — FIND THE CORRECT $
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LOT OF HASSLE.

FOR YOUR ENTERTAINMENT:

1. AHAMUR — RULE YOUR OWN IS-
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Driving an automobile or playing a flight
simulation game with a keyboard is

just not natural.

your computer. Although it is rugged and
can be reasonably handled, it is mainly
made up of CMOS gates which can be
permanently put out of action by a small
static discharge. When working with
CMOS circuits, I make it a policy never
to wear sweaters or synthetic clothing or
to work around plastic sheets, carpet,
dogs, cats, or kids. Kids do not usually
carry a lot of static charge, but they do
have a tendency to drag all your parts
into the floor when you are not looking.
Try to discharge any static before touch-
ing the PC board. This can be done by
touching a heavy metal object. Always
use a high quality soldering pencil, pre-
ferably a grounded type, to insure against
voltage transients from the iron.

Testing the Joystick

Plug the new controller into your con-
nector and turn on the computer. A for-
ward movement of the stick should pro-
duce a “7”and a backward direction will
produce a “6.” Left and right should pro-
duce a “5” and “8” respectively. I wired
the “fire” button to “9” because it was
convenient, but you can wire it to the
character you prefer.

If you only get a blink of the cursor and
no character, either you have shorted one
of the matrix lines to each other or one of
the switches in the joystick is stuck closed.
If you get a wrong character, you have
misconnected one of the KB and D lines.
Remove the controller from the con-
nector; entry from the original keyboard
should return to normal.

The only big disadvantage to this ar-
rangement is that a diagonal direction
cannot be achieved. I feel, however, that
with the combined use of the fire button,
this function could be easily
programmed.

Rewriting Existing Programs for the New
Joystick

The improved operation of the flight
simulation program was so dramatic that
I decided to rewrite all of my graphic
programs to respond to the cursor keys.

My screen drawing program, "Sketch-
pad," is now a real joy to use. The three
year-old from next door now loves
"Sketch-pad," but he would not even try
it with the keyboard. The program is
shown in Listing 1 for those of you who
would like to try your artistic hand with
the new joystick. The "fire" button is used
to select between either erasing or draw-
ing. Pushing the button causes the pixel
to erase itself as it is moved. Then, by
pushing the button again, drawing can be

continued. This handy little feature allows
you to erase any errors or move the pixel
to another location to start another line.

Listing 1. Sketch-pad program.

5 REM "SKETCH-PAD"

19 CLS

15 PRINT "DRAW"

20 PRINT "Z-CLEAR"

25 PRINT "USE FIRE BUTTON FOR ERASE"
45 LET X-3f

5Ø LET Y=29

55 IF INKEY$="9" THEN GOTO 135
60 IF INKEY$="7" THEN LET Y=Y+1
65 IF INKEY$="6" THEN LET Y=Y-1
7f IF INKEY$="5" THEN LET X=X+1
75 IF INKEY$="8" THEN LET X=X-1
80 IF INKEY$="Z" THEN RUN

85 PLOT X,Y
115 UNPLOT X,Y
120 PLOT X,Y
125 GOTO 55
13Q IF INKEY$="9" THEN GOTO 69
135 IF INKEY$="7" THEN LET Y=Y+1
149 IF INKEY$="6" THEN LET Y=Y-1
145 IF INKEY$="5" THEN LET X=X+1
159 IF INKEY$="8" THEN LET X=X-1
155 UNPLOT X,Y
160 PLOT X,Y
165 UNPLOT X,Y
170 GOTO 139

Most Basic programs use one or two
methods to control the movement of the
PRINT or PLOT command. This is
usually done using the INKEYS function
and usually lets some variable equal
PEEK 16421. This location is the storage
area of the value obtained from the key-
board scan done after each TV frame.
However, the code that is stored in this
location is only a value that lets the com-
puter know which section of the keyboard
is being pressed. That is, the character 5
would have its own value but the char-
acters 6 through 9 would all have the
same code since they are all located in
the same keyboard section. This method
is slightly faster, but will work with the
cursor controls. The PEEK method will
have to be replaced with the INKEY$
function as in Listing 2.

Listing 2. Rewriting the PEEK method...
100 LET X = PEEK 16421

139 IF X=(239) THEN LET Y=Y+1

Change To:

130 IF INKEY$ = (your character) THEN
LET YzY*1

Delete line 109

You will find that the trouble of re-
moving the case back and the soldering
of the connector will be well worth the
effort when you see how easily the graph-
ics now respond.

The $8.50 turned out to be a good
investment. a"

July/August 1983 ° SYNC

YOU CAN HAVE

ALL THE ANSWERS

With the most complete Sinclair software library available.

by
DE. HAN LOGAN

UNDERSTANDING YOUR ZX81 ROM

by Dr. lan Logan

SYNC Magazine said: "SYNC readers will recognize
Dr. Logan as a major ZX80/81 expert whose writings
are well worthwile. Understanding Your ZX81 ROM is
no exception. The book falls logically into five parts:
a brief review of the Z80 CPU, next a quick intro-
duction to the internal arithmetic and number base
manipulations; a discussion of the Z80 machine code
instructions grouped by function; a detailed exam-
ination of the relevant parts of the 8K ROM; Dr. Logan
introduces machine code programming by treating it
as an extension to Basic; and complete listings of the
more important 8K ROM routines are given as well as
the usual tables of machine code language
instructions, decimal-hexadecimal conversions, and
keycodes. Understanding Your ZX81 ROM should be
high on your list.” Now available for only $14.95

MACHINE LANGUAGE PROGRAMMING
MADE SIMPLE

Michael Roberts, SYNTAX Magazine wrote:

"| wanted to review this book because I’m the person
it was written for. | taught myself BASIC and can

now do most of the things | want to with it. | felt that
Machine Language would be a good addition to
speed up some programs and improve display. The
idea of Machine Language 'made simple' appealed
to me. It's the best explanation of Machine Language
for Machine Language beginners l've seen.

the Completa vri
Snolate X81 & Timex WII Y
Radic Cattrac

30 PROGRAMS
FOR THE
SINCLAIR

Its friendly style is painless reading g
analogies help make this language

This introduction is a must.’ Now o E LIIS
only $14.95 Sanus
NOT ONLY 30 PROGRAMS,

is a collection of programs for tl,
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PEEK and POKE explained, full ga T,
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can be crammed into Sin -
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disassembled the 8K monitor program of the ZX81 /
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2K To 4K RAM Upgrade
— An Introduction To ZX/TS Hardware

Introduction

Aside from the obvious fact that the TS1000 is an incredibly
powerful computer for the money, it has a barebones simpli-
city in its hardware design that invites the user to explore and
learn the hidden secrets of its digital circuitry. This hardware
project will upgrade your on-board 2K RAM to 4K (or more)
for under $10 and provide you with the opportunity to learn
something of the elegance of computer electronics, with
(hopefully) minimal risk of destroying your computer in the
process.

Although this article applies to the TS1000 with 2K RAM,
it will also work just fine with a ZX81 with the 2K RAM
upgrade. (See J. Wayne Schneider's excellent article in $ YNC
2:4 for 2K expansion details).

Hardware projects with the TS1000 are not really difficult
since there are relatively few major components to deal with
and the printed circuit board is laid out in a fairly logical
fashion. It does, however, require more than just *cook book"
knowledge to complete this project successfully — success
being measured both by what has been accomplished and by
what has been learned along the way. RAM expansion is a
good example of a hardware modification that will give you
exposure to some of the basic concepts of computer hardware
design and function, and perhaps provide a foundation for
further projects and experimentation. But most of all, I hope
you will find that it is fun to get your hands on the circuits and
make the computer do something new for you.

Part 1 of this article deals with the theory needed to
understand the circuit modifications that will be made. It
assumes that you know a little about binary numbers and
simple electronics. If you want to learn the theory without
voiding your warranty (which happens if you open up your
computer during the warranty period), just read Part 2 which
describes the construction and testing of the RAM expansion.
Those of you who already understand all the concepts in Part
1 are excused to go immediately to Part 2.

Part 1

1) Binary

Since computer address and data lines are coded in binary,
you need to know the binary system in order to understand
how data is shuffled about in the TS1000. If you do not know

Randall S. Glidden, M.D., 185 Chiswick Rd., Brighton, MA 02135.

Randall S. Glidden

binary, take the time to learn it before you begin.

2) Digital Circuits

Electronically speaking, binary logic ls and 0’s can be
represented by high and low voltages, respectively. In most
digital circuits +5 volts = 1 and zero voltage (ground) = 0.
This has been compared to a switch being either in the “on”
or the “off” position; however, this is misleading. A digital
logic zero should always be thought of as a wire connected to
ground and not as a wire disconnected from voltage.

Another way to look at this is that a logic 1 sources +5
volts to a particular wire or device, while a logic 0 sinks
voltage coming from that device to ground. Obviously, if a
wire is connected neither to +5 volts nor to ground then it
will be unable to source or sink current.

From this point on keep the following in mind:

5 Volts — logic 1 — high.

Ground — GND - 0 Volts — logic 0 — low
These will be used somewhat interchangeably.

3) TS1000/ZX81 Circuitry — Overview

The circuitry of the TS1000 can be divided into the follow-
ing components (Refer to the photograph in your TS1000
Basic Programming):

a) Power source and +5 voltage regulator with a bunch of
capacitors to provide a constant, smoothed, 5V power
supply.

b) Z80A Central processing Unit (CPU): A 40 pin integrated
circuit which performs all the “computing” functions. To
make the Z80 ready to do Basic after you turn it on, it must
receive operating instructions from the 8K ROM.

c) 8K ROM: A Read Only Memory which provides, in a
sequential order, all the commands required so that the CPU
can provide Sinclair Basic to the user. The commands are
"byte" sized (i.e., decimal values 0 to 255) machine code
instructions which occupy memory addresses 0 through 8191.

d) 2K RAM: Random Access Memory which is used for
temporary storage of the program and the operating system
variables (used by the ROM and CPU).

e) Sinclair Computer Logic chip: A conglomeration of
logic gates and other circuitry which ties together the other
components, generates the video display, provides circuitry
for SAVE and LOAD, encodes the keyboard for the CPU,
etc.

f) Miscellaneous stuff: VHF video modulator, clock circuits,

July/August 1983 © SYNC

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keyboard interface, expansion port, etc.

The functioning of all these components is beyond the
scope of this article, but we do need to discuss how the Z80
CPU is tied in to the RAM and how to modify it to suit our
purposes.

4) Z80 CPU

Most of the 40 pins of the Z80 can be divided into three
groups (see Figure 1):

a) Control signals

Since these are the most difficult to deal with conceptually,
we will ignore most of them. Suffice it to say that these carry
signals either to the CPU (and therefore telling it to do
something) or away from the CPU (and telling another device
to do or get ready to do something). Without the control
lines, the CPU would sit idly by, not knowing what to do next.

Let's consider RD and WR which are signals from the Z80.
These can tell the RAM or ROM that the CPU wants either
to ReaD something from memory or to WRite something
(RAM only) into memory. The bar over the letters is read as

"not WR," which means that during a write operation, when

WR becomes active, a logic zero is present at that pin. Le., if
a device is to respond to that signal, it must be activated by a
0 and turned off by a 1.

Figure 1. Z80 CPU.

Address | A133

Address

D2 0 volts
D7
Data
DO
pı 45 26 RESET
INT 16 25 BUSRO
NMI 17 24 WAIT Control
Control { HALT 18 23 BUSAK
MREO

b) Address Bus

Sixteen separate, parallel lines (collectively called a bus)
carry signals from the CPU to another device (RAM, ROM,
etc.). They tell it the location of a particular byte of data.
These lines are indicated by the abbreviations AQ through
A15. The AO line represents the least significant bit (LSB) of
a 16 bit binary number, and therefore it can have the decimal
value 1 or 0. A15 is the most significant bit (MSB) so, when it
carries a 1, it has the decimal value 32768. Since all 16 lines
can carry either a 1 or a 0, the address bus can code, in
binary, any number from decimal 0 to 65535.

Transmission of an address along the address bus is done in
a parallel fashion, i.e., if address 65535 is called for, then 1's
appear simultaneously at all 16 of the address bus lines for a
brief instant. Many of the address lines are connected to
corresponding address pins of the memory devices, as you
will soon see.

c) Data Bus

This is similar to the address bus in that it is a parallel set of
lines which carry signals from the CPU. It differs in that it
also carries data to the CPU (i.e., it is bidirectional). In
addition, it has only 8 lines (DO through D7) instead of 16. DO
is the LSB (equals 0 or 1, decimal) and D7 is the MSB (equals
0 or 128, decimal). So on the data bus, any number from 0 to
255 can be sent to or from the CPU.

d) Other pins

Besides a +5 volt and a ground pin, there is a clock input

(marked Ọ ). This pin receives a 3.5 MHz pulse from the
clock circuitry, thus providing the all important timing of the
sequential steps the CPU must take, whether it is running a
program or just sitting there with a K in the corner.

5) RAM: The Toshiba 2016

The TS1000 uses the 2016, a 24 pin, 2048 word x 8-bit, high
speed static RAM. It can contain 2048 different bytes of
memory or a total of 16384 different bits. It has the memory
capacity of a two to three ton vacuum tube memory bank of
the 1950s vintage and probably costs less than a single vacuum
tube did back then!

The set-up of most of the 24 pins is similar to that of the
CPU: 11 address bus pins (A0-A10), 8 data bus pins (DO-D7),
3 control pins, and +5 volt and ground pins. The 11 address
lines will code for any number from 0 to 2047; the 8 data
lines, for 0 to 255.

Figure 2. 2016 2K RAM... . —

The three control inputs simply tell the RAM chip what to
do. CS is the chip select, and it is effectively the on/off switch
for the chip. This pin is connected to a control line from the
Sinclair Logic chip called RAM CS. As before, the bar over
“CS” means that it is active when this pin is low— i.e., the chip
is selected or enabled when CS is low. When the chip is not
needed, a logic 1 is present at CS and nothing happens.

Besides being turned off when CS = 1, the data bus lines
will be in a high impedance state (also called tristate) at those
times. This means that those lines are effectively disconnected
from the rest of the circuitry — current will neither flow
through nor from the data pins when CS=1. The tristate
concept is important since most, if not all, of the data and
address buses are shared by so many different components.
This effectively keeps them isolated from each other.

RD is the READ enable. When it is low, data from a
particular location in memory is available to be placed on the
data bus and thus READ by the CPU. WR is the WRITE

Table 1. Truth table for 2K RAM chip
(TMM-2016 or equivalent).

a
3

Mode of Chip Condition of data pins

Not selected High Impedence
(turned off) (tri-state)

GET

1 WRITE Data in
0 WRITE Data in

1 = +5 volts, high
0 = Ground (0 volts), low
X = Does not matter; could be 1 or 0

þh

July/August 1983 ® SYNC .

enable. When it is low, data coming into the data bus can be
written into a specified memory address. Since you cannot

Table 2. Memory address decoding.

Memory blocks
Address Value 1st 2048 byt

e 2nd 2048 bytes 3rd 2048 bytes
Bus Line (decimal) (16384-18431) (18432-20478) (20479-22526)
A15 215232268 0 0 0
Als 21-1638, 1 1 1
A13 23. 8192 0 0 0
A12 217. 4096 0 0 1
All 2!l- 2048 0 1 1
A10 219. 1024
A9 27 = 512
A8 28 = 256
A7 27 = 128
A6 225- &
Memory addresses occupied by
AS aS 32 each 2K RAM chip, i.e., 2048
bytes (0-2047) or any binary
AL at fh 16 combination A0-A10
A3 293 38
A2 23 t4
Al 25g 7:9
AO 29 = 1
Summary of decoding for 8 2K Blocks.
2K Block # All A12 A13 A14 A15
L 0 0 0 l 0
2 l 0 0 1 0
3 0 l 0 1 0
4 1 1 0 1 0
5 0 0 ait 1 0
6 T 0 JT n 0
Zz 0 it 1 Jd 0
8 l d: l iL 0

Table 3. 74LS138 Truth Table.

INPUTs OUTPUT; (CS) RAM chip #

X
al
X
0
0
0
0
0
0
0

Eyes RU er LU RU [Hee 9 »

o o o o o o o o P Lad rH
Fr rm H} we e o o o > ps Lad
m Lr [e] eo ro = o o >

r2 o be o ra o we o >< 7

rn rn r^ to rn od Hr o rm rn E
be e bt rm be rm o = = r= rm
H} be od w rn o be od we a rn
n | = rn o H = rn be a rm
rm rn rm O = = (g r Pr [n rm
be H o rn be [x — = (a H} rnm
= o rm bw Hd rn = rn = = rR
o = rm rn H} be a H = w be

o
rp

1 = +5 volts, high
0 = Ground (0 volts), low
X = Does not matter; could be 1 or 0

Figure 3. 74LS138 1 of 8 decoder.

Select
inputs B

G2A

Enables { G2B

74LS138 Gutpllis

Output v7

O volts

READ and WRITE data out of/into memory at the same
time, the chip is set up so that WR must be high (i.e., inactive)
when RD is low (active) in order for a READ to take place.

For a WRITE into memory to take place, WR must be low,
but (for reasons of simplifying hardware design) RD can be
high or low. In fact, the TS1000 ties RD permanently to
ground; READ and WRITE operations are thus based entirely
on the condition of WR (and CS of course). See Table 1.

In summary then, if CS is high, the 2016 is turned off and it
does not matter what is present at WR or RD. When CS is
low, a WRITE into memory what is present at WR or RD.
When CS is low, a WRITE into o memory will occur if WR is
low, and a READ will occur if WR is high (since RD is always
low anyway). ,

6) The Decoder

A RAM pack, such as the Sinclair 16K pack, consists of
several separate memory chips wired together in parallel.
From our examination of the 2016, it should be clear that in
order to expand our on-board memory we must have some
way of sequentially selecting the chips we add, just as the
different RAM chips in a large memory pack are selected.
This is done by a decoder circuit, a logic circuit which simply
divides a large number of memory addresses among several
discrete memory chips. In other words, suppose we have
eight 2K RAM chips. We could have a total 16K of RAM if
we had a circuit that would apportion that 16K into separate
2K chunks. In a more global sense, the decoder circuits in the
TS1000 decide which of the 65535 potential addresses are

. locations in RAM, ROM, or whatever.

The TS1000 decoder is located in that giant Sinclair Logic
chip, and basically does its work based on the condition of
A14. The ROM is enabled if A14 = Q (i.e., O to 16383,
decimal), and the RAM is enabled if A14 = 1 (i.e., addresses
16384 and above). (A15 is used in the video display and
prohibits use of the 32K memory block above 32767 without
some special outside decoding circuits.) When RAM space is
needed by the CPU, the decoder enables the on-board RAM
by sending a "0" through the line RAM CS, which is tied to
the CS pin of the 2016. Since RAM CS is low at any address
between 16384 and 32767, we can use RAM CS to help select
any additional chips we may put in that space. What we must
do, however, is provide for further decoding of that 16K
block.
Table 2 shows the decimal representation of the value of
each address line, A0-A15. If we are using 2048 byte chips
that are all wired in parallel to A0-A10, all we have to do is
use the status of the upper address lines (A11-A15) to decide
for us which chip should be enabled for a specified location in
memory.

The bottom portion of Table 2 shows that eight different
chips, or a full 16K, can be selected using just A11, A12, and
A13 (since there are eight combinations of a 3-bit binary
number). Since A14 is always 1 and A15 is always 0 from 16K
to 32K, we can ignore them and use just A11-A13. What we
need is a circuit that will take a 3-bit binary number as input
and give us eight different outputs that can be used to select
our memory chips. Luckily someone invented the 74LS138!

7) The 74LS138

The 74LS138 is a 16 pin IC that functions as a “1-of-8
decoder/demultiplexer." The block diagram (Figure 3) and
truth table (Table 1) give some idea of how it operates. As
with the 2016, this chip must also be enabled to be functional.
It differs in that there are three different enable inputs, two
active when low (pins 4 and 5), and one active when high (pin
6). The truth table shows that, unless pins 4 and 5 are low and
pin 6 is high, the outputs at V0-V7 will all be high, regardless
of the condition of the three inputs: A, B, and C. When the

July/August 1983 © SYNC

chip is enabled, different inputs at S, B, and C (from 000 to
111, binary) produce a logic 0 at one of the eight outputs, VO-
V7

Now, if we connect A11, A12, and A13 to inputs A, B, and
C, respectively, and then connect the “V” outputs sequentially
to our 2K RAM chips, we will have our decoding problem
almost solved. To enable the 74L S138 itself we can use the
RAM CS line from the logic chip and connect it to enable
pins 4 and 5 (remember, active low). To keep the "high"
enable high we can just permanently connect pin 6 to +5
volts. To make matters even simpler, if you are only adding
one or two extra 2K chips, you can skip the connection to
A13, since this is a O for the first four 2K blocks anyway. Just
connect input C to ground, in that case, making it a permanent
0.

Congratulations! If you have made it through all that, you
could probably do the memory expansion project without
reading any further, since all we have to do is connect the
74LS138 to GND, +5 volts, RAM CS, A11, and A12 on the
TS1000 circuit board, and connect two of the 74LS138 output
pins to the CS pins of two 2K RAM chips stacked on top of
each other. All you really need to know now is the location of
the necessary lines on the circuit board and some of the
practical construction points. These will be covered in Part 2.

Part 2

Now we will dive into the actual construction details of our
RAM expansion. Hopefully you are already familiar with
which end of a soldering iron gets hot, and perhaps you
already have some (or all) of the equipment listed below.
Since it is a little tricky soldering connections directly to
integrated circuit pins, I recommend that you buy an inex-
pensive wire-wrapping tool and make the connections that
way. Provide yourself with a clean, well lit work space, get
together all the necessary materials, and have fun!

Materials

1) A 2Kxó static RAM. Although I have discussed the
Toshiba 2016 above, I recommend the Hitachi, HM 6116LP-
4. JDR Microdevices, Inc. sells the 6116LP-4 for $6.95 (at the
time of this writing). You can get a 6116-4 (not LP, low
power) for $4.95, but it uses slightly more power— a consider-
ation if overheating is often a problem. The 2016 (TMM
2016-200) is the cheapest 2Kx8 RAM on JDR’s list, selling for
a mere $4.15. It does, however, use more power than any of
the 6116s, but all the pin designations are exactly the same.

Note that when you see a catalog listing of these chips you
will see that the access times are listed in many cases. For
example, a 6116-4 has an access time of 200 nanoseconds
while a 6116-2 has an access time of 120 nanoseconds. The
Z80 CPU uses about 900 nanoseconds to access a RAM chip,
SO it is not necessary to spend more money for the faster
chips; better to get the low power RAM and save on power
requirements instead.

By the way, I recommend JDR as a source for IC chips
because they always have a catalog type ad at the back of
every issue of Computers and Electronics (formerly Popular
Electronics), they have a toll-free number for charge card
orders (800/662-6279; California only), their prices are as low
as you are likely to find, and they ship fairly quickly. They do
have a $10 minimum order, which is more than you will need
to spend in parts for this whole project! But you can stock up
on a few other parts to pad out your order. Their address is:
JDR Microdevices, Inc., 1224 S. Bascom Ave., San Jose, CA
95128.

2) A 74LS138, 1-of-8 decoder. $.55 from JDR or $.99 from
Radio Shack.

3) A 16-pin solder-tail DIP IC socket. $.17 from JDR.

July/August 1983 ° SYNC

Figure 4. Decoder wiring diagram.

(A13)A12 All SV

Connection to A13 not AA
needed if using less than CS. CS!

2K RAM chips (dotted line). To pin 18 of
If A13 is used, do not connect 2K RAM chips
pin 3 to ground. drain:

(GND)

4) 30 gauge wire-wrap wire. Radio Shack 278-500 series, or
equivalent.

5) Double-sided tape or rubber cement.

6) Rosin-core solder.

Tools

1) A 15-25 watt fine-tipped soldering iron.

2) A small wire-wrapping tool. Radio Shack 276-15700, or
equivalent.

3) A sharp, fine pointed knife, e.g., X-acto.

4) A small Phillips-head screw driver.

5) Needle-nose pliers.

Construction Overview

You will see from the schematic (Figure 4) that all we are
doing is wiring the 74LS138 to the board and connecting two
(or more) of its outputs to the CS pins of two (or more)
stacked 2K RAM chips. The connections to the 74LS138 will
be made by wire-wrapping directly to its pins and making a
few solder connections to the TS1000 circuit board. To hold
the chip in place we will use a 16-pin DIP socket with its pins
removed and its socket holes enlarged with the X-acto knife
accommodate the wire-wrapped IC pins. The 74L S138 in its
socket will be attached to the board in the space between the
RAM and the CPU using either double-sided tape or rubber
cement. The RAM chips will be stacked on top of each other,
with the upper chip pins bent inward slightly to make contact
with the lower chip pins. The CS pins will be bent outward,
and connected to the 74LS138 with wire-wrapping connec-
tions.

Step-by-Step Construction

1) Remove the TS1000 circuit board from the case.

Turn the computer upside down so that the expansion port
is pointed away from you. Remove the five Phillips head
screws, three of which are under the lower two and upper left
rubber pads. Remove the pads carefully and set aside. Note
that the lower two screws are shorter than the upper three,
and be sure you put them back that way when you are done.
Remove the back and set it aside.

2) Remove the circuit board.

Remove the two screws holding the board in place, noting
their position. Turn the board over and carefully pull the
keyboard tails out of the board connectors. (Do not bend or
kink the tails in the process.)

3) Locate the land marks.

With board oriented in the same way as the photograph
(Figure 5) locate the 2K RAM chip, the CPU, and the
expansion edge connector strip. Since the TS1000 uses the
same board as the ZX81, do not be surprised when you see
"Sinclair ZX81" stamped in the upper right-hand corner!
Between the CPU and the RAM chip is a space marked IC4a.
This was used in many ZX81s as half of the 1K memory, since

Figure 5. TX/TS circuit board with added 74LS138 and 3 stacked 2K RAM
chips.

qu had two 1028 x 4 bit chips instead of a single 1028 x 8
chip.

4) Wire the 74LS138.

Practice making a few wire-wrap connections on some
spare parts. Then you can make the connections shown in
Figure 4. First connect pin 16 (+5 volts) to pin 6 (the
permanent 1 enable), and then connect pin 3 (input C) to pin
8 (ground) using short wire wrap connections. (Recall that for
the first four RAM chips we do not need A13, which would
be input C. We will just hook it to ground, making it a
permanent 0.)

Prepare seven 2 to 3 inch lengths of wire-wrap wire with
1/4" insulation stripped from one end and 1/2" stripped from
the other. Wire-wrap the 1/2" ends to. pins 1, 2, 4 and 5
(together), 8, 14, 15, and 16. (If you are stacking more than
one RAM chip, you will need additional wires at pins 13-9, as
shown in the schematic.)

5) Prepare the socket.

With a pair of pliers pull all the solder-tail pins out of the 16
pin DIP socket. They should pull right out. With the X-acto
knife enlarge the socket holes wherever a pin with wire-wrap
is to be placed, and then see if your wired 74LS138 will fit into
it. You will probably have to bend the pins inward a bit to do
this. You should get a nice snug fit so that the IC will not pop
out of the socket when you put the computer back together.

6) Solder the 74LS138 to board.

Figure 6. Location of holes for solder connections.

RAM CS

OOO 23A
1A ooo Oo
Sinclair ZX81 O [e o
o
R15 R16 R17 5 All
A12
Issue O O
ssue One Eu | l | Oo ó A13
C
IC3 IC4
45V.

Labels correspond to those found on the TS1000
or ZXS81 circuit board.

You will need to make five solder connections to the
circuit board. As long as you do not touch the tip of the
soldering iron to the ICs on the board you should cause no
damage while soldering, so I do not recommend you remove
all four ICs. It is helpful to have your TS1000 operable during
this part of the construction so that you can turn it on after
each solder connection and see if it still works, as a solder
short will yield a blank or broken screen. This makes trouble
shooting much easier.

With the power to the computer off, place each wire from
the 74LS138 in turn into its appropriate hole as shown in
Figure 6, and solder it in place, using as little solder as
possible. (Hint—tinning the ends of each wire with solder
beforehand allows two-handed soldering, rather than the usual
"three-handed" method.) Be careful the solder has not shorted
across to another circuit tracing— check each side of the
board for this. After each soldered connection test the
computer by hooking it to the TV and applying power— you
do not need the keyboard hooked up to get a K cursor. If at
any point the K does not appear after you have made a
connection, do not panic. Just check the connection carefully
and resolder if necessary.

7) Stack the RAM chips.

Take the RAM chip you are going to add, and orient it
over the on-board RAM chip. Locate the dent at the top end
of the chip so that it lies above the dent end of the board
RAM chip. You will see that the pins of your upper chip
probably do not make contact with the lower chip pins. Place
the edge of the chip on a flat surface and apply gentle
downward pressure to bend all the pins on one side inward
slightly. Repeat this on the other side and try stacking the
chip again. Continue bending the pins inward, a little at a
time, until all the pins make firm contact with the pins of the
lower chip. Since the RAM chips are wired in parallel, except
for the CS pins; this snug fit is of the utmost importance for
Success, jd

Now locate the CS pin (pin 18), and bend it outward so that
it is at a right angle to the other pins. Now replace the chip in
its protective foam for now and set it aside.

Carefully remove the on-board 2016 RAM chip by alter-
natively prying up at each end with a small screwdriver. Be
careful not to bend the pins. Locate pin 18 again (CS) and
bend it outward as you did with the chip to be added. Replace
the 2016, with pin 18 sticking out sideways, out of its socket.

8) Final connections and testing.

Wire-wrap the wire from pin 15 of the 74LS138 decoder to
pin 18 of the on-board RAM. Power up the computer and see
if it works, now that the on-board chip is connected to the
decoder. If it does not work, go to the “Trouble shooting." If
it works, pat yourself on the back and then wire-wrap pin 18
of the other RAM chip to the decoder pin 14, and stack the
chip on top of the on-board chip. Be sure that all the pins are
making firm contact with each other (except, of course, pin
18). Although Figure 5 shows three 2K chips stacked together,
your board should now look similiar.

Apply power again and see what happens. After a delay of
about 3-4 seconds you should see the K cursor appear. Now
comes the moment of truth: reconnect the keyboard tails and
check the memory RAMTOP setting by typing in:

PRINT PEEK 16389*256-16384

You should then see 4096, the amount of RAM available. If
that is what you get, then pat yourself on the back again, have
a beer, and go show your wife/husband/significant other the
wonderful thing you have done. If you get 2048 that just
means your added RAM chip is not making firm contact with
all the pins; reposition it and try again.

9) Reassembly.

After playing with your new 4K RAM a bit, you will
probably want to anchor the added RAM chip to the board

July/August 1983 © SYNC

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chip either by applying double sided tape to its side or by
gluing with a thin layer of rubber cement. This will keep the
chip from popping off after reassembly. I would advise against
using epoxy or super glue, since it is possible you may want to
remove or adjust the placement slightly in the future without
the aid of a hammer and chisel.

Some people with much CMOS expertise may wish to
solder the two chips together. This is dangerous to the life of
your RAM chips unless you have had considerably more
experience than most in doing this. You must use a soldering
iron with a grounded tip and be a bit more cavalier than I am
to attempt it; so do so at your own risk!

Now attach the 74LS138 socket to the board using double
sided tape or rubber cement. Make sure none of the IC pins
are extending through the socket; this could cause a short.
You may want to insulate the socket with some electrician's
tape to safeguard against this.

Try to tuck the wires from the decoder out of the way,
since the keyboard tails will be lying directly over it when the
computer is reassembled.

Now, make sure the added RAM still works, and the replace
the circuit board in the case and close up. Be sure you use the
proper screws. Reattach the rubber feet, using rubber cement
if needed.

Beyond 4K

If you have your circuit board mounted inside some kind of
big keyboard enclosure with enough room, you can stack up
to eight chips (in theory at least — I have stacked only three).
Just bend out pin 18 of each chip and wire-wrap one of the
other output pins from the decoder to it. If you do this, I
would especially advise using the 6116-LP4s, keeping the
power requirements to a minimum. Unfortunately, there is
only room for one extra chip under the hood of a standard
TS1000.

Trouble Shooting

The following problems are the ones you will most likely
encounted.

1) K cursor will not appear or zig-zag lines appear. Look for
solder shorts and for poor solder connections. Are all the
solder connections made in the correct holes? Also beware of
steel wool dust—a common work shop containment. It can
microscopically short across some of the closely spaced
traces.

Make sure you wired the 74LS138 correctly and that none
of the wire-wrap connections are shorting each other out.
(You did not wire the chip backwards, did you?) Also make
sure you wired the decoder to pin 18 of the RAM chips.

If all else fails, it is possible you have a bad 74LS138; get
another and try again. (This does not happen very often.)

2) Can only get 2K of RAM. Make sure all the RAM pins
are making firm contact with each other. Try bending them
all in a bit more. Make sure that pin 18 of one RAM is not
touching that of the other RAM. See that the connections
from the decoder to the chips are good.

3) If you have any other trouble please send me a descrip-
tion of your problem along with a self-addressed stamped
envelope, and I will try to help you if I can.

Conclusion

Well, that is about it. I hope that your RAM expansion has
been successful, and that you will now want to try your hand
at other hardware projects. Having an expansion board is the
best way to take on serious hardware design, since all con-
struction is done on separate boards, thus posing less risk to
your main computer circuits.

I welcome any comments, constructive or otherwise, from
SYNC readers.

July/August 1983 ° SYNC

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Stringing along with the ZX81 Paul J. wentink

The DATA-READ statement is the
basic computer command for the efficient
storage and use of data comprised of
many values (bulk data) where data is to
be used repetitively in a program or where
data is to be retained for successive com-
puter runs. Such data might consist of
names and addresses, names and phone
numbers, football scores, degree days,
inventory part numbers, star brightness
intensity, input from an RS222 port, and
on and on and . . .

As we are aware, the ZX81 does not
include these statements. The Z X61 Basic
Programming manual by Steven Vickers
suggests the use of LET X=N type state-
ments to duplicate DATA statements.
This, unfortunately, requires the extensive
dedication of memory for data storage
except for short programs. Another
method of achieving a ZX81 DATA-
READ capability would be through ma-
chine language. This would require a very
thorough knowledge of the Z80 CPU
assembly language. There is, however, a
method of simulating DATA-READ state-
ments on the ZX81 using string state-
ments, slicing, and the LEN/VAL
functions. This method does not require
the use of machine language nor does it
require excessive memory. Furthermore,
it can be easily mastered if the use of
string statements as presented in the
ZX81 Basic Programming manual is
understood.

The proposed method consists of enter-
ing data as a string statement, slicing the
characters from the string which make up
a data-set, converting the sliced substrings
to a numerical value, if necessary, and
then using these substrings as program
variables.

The ZX81 DATA-READ simulation tech-
nique is generally developed in accordance
with the following steps:

Step 1. Enter all data in a string statement
(LET AS—*XXXX") so that each data-set
within the string can be identified repetitively

Paul J. Wentink, 36102 S.E. 49th St., Fall City,
WA 98024.

by character position within the string.

Step 2. Set up an array which will permit
each data-set to be assigned a unique address
in the array as it is sliced from the string, or
originate statements which will selectively
slice data-sets from the string to be used di-
rectly as program variables.

Step 3. Read data-sets from the array or
string as applicable, convert data to numeric
values if necessary and use as program
variables.

Since data entered in a program using this
method is always directly addressable, there is
no need for the RESTORE command which is
usually associated with Basic DATA-READ
commands.

To demonstrate the ZX81 DATA-READ
simulation technique, five programs are pre-
sented of varying complexity showing first
the DATA-READ program in Basic Language
which is not usable with the ZX81 Computer,
and then equivalent programs written for use
with the ZX81. Program Listings 1A through
IE are all equivalent programs consisting of a
data statement containing a number of data-
sets from which data is read and then used in a
simple arithmetic calculation. Program List-
ings 2A through 2C are all equivalent pro-
grams demonstrating a ZX81 DATA-READ
simulation for data which is NON-NUMER-

Listing 1A. Conventional Basic
READ-DATA Program.

05 REM LISTING 1A
10 READ A,B,C,D
20 PRINT A*B;CTD
30. DATA. 5,10,15,20

IC. Program Listings 3A through 5B are a
series of three similar programs of increasing
complexity wherein a data-set counting pro-
gram tallies the number of times a data-set of
like value occurs in a data statement.

Program 1

Listing 1A is a program written in con-
ventional Basic using DATA-READ state-
ments which cannot be executed on a ZX81
Computer.

Listing 1B is a program, equivalent to list-
ing 1A, which can be executed on a ZX81
Computer. The program simulates a DATA-
READ capability by entering the data as a
string statement with all data-sets expressed
as two characters separated from other data-

Listing 1B.
ZX81 Simulation of DATA-READ Statement
Using a Fixed Size Addressable Array.

05 REM LISTING 1B
10-LET A$2*05,10,15,20;,"

20 DIM A(4)

36 DET KSI

40 FOR J=1 TO 4

50 LET Y=X+1

60 LET A(J)=VAL A$(X TO Y)
70 LET X=X+3

80 NEXT J

90 PRINT A(1)+A(2),A(3)+A(4)

g/ 9g

sets with commas for visibility (line 10).

An array is then dimensioned to accept the
data-sets so that each can be addressed by
name when used as a program variable (line
20). The data is sliced from the string and
entered by value into the array (lines 30-80).
Numerical calculations are then made using
the data as addressed within the array (line
90).

Listing 1C is the same program as Listing
IB except that the array is not dimensioned for
a fixed size but is set up equal in size to the
number of data-sets existing in the program.

July/August 1983 © SYNC

Joi

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Listing 1C. ZX81 Simulation of DATA-READ
Statement Using a Variable Size Addressable
in cr xn ATTIV:

05 REM LISTING 1C

10-LET A$2^05;10,15520;"

20 DIM A(LEN A$/3)

30 EET Jeet

40 FOR J=1 TO LEN A$/3

S0 DET Yee

60 LET A(J)*VAL A$(X TO Y)

70 LET X=X+3

80 NEXT J

90 PRINT A(1)+A(2),A(3)+A(4)

D5 22

6/99

Each data-set, again, is expressed as two
characters separated by a comma. Thus the
array size must equal the total number of
characters entered into the data string divided
by 3 or LEN A$/3 (line 20). Since the size of
the array will now adjust to the number of
data-sets in the data string, the program loop
entering the data into the array must likewise
vary in length. This is accomplished by enter-
ing LEN A$/3 into the loop command (line
40).

Listing 1D is the same as Listing 1C except
that new data has been added to the program
in a new string command (line 901), the origi-
nal A$ command has been adjusted to include
the new B$ data (line 990) and the variable
size array has accepted the new data without
revision to the program. Thus new data has
been added without need to re enter previous
data or making any program deletions. It
should be evident that additional new data en-
tries can be made in like manner by entering
up to 26 new data strings of any length, i.e.,
C$,D$, etc, and then including those strings
in line 990. For example:

900. LET:A$-505,10. 15.20,

901 LET. B$-2"25,30,35,;40,"

902 LET.0$- 45,50;

903- LET «D$="554605655:70475,80.85,"

990 LET A$=A$+B$+C$+D$

999 GOTO 20

Listing 1E is the same program as Listing
1B except that the data is not addressable
within an array but is rather sliced from the
data string and used directly as substrings as
program variables.

Program 2

Listing 2A is a program show in the ZX8/
BASIC Programming manual as an example of
ZX81 incompatibility with conventional
Basic DATA-READ statements.

Listing 2B is a program equivalent to List-
ing 2A which can be executed on a ZX81
Computer. The simulation of a ZX81
DATA-READ program follows the same
technique as explained for Listing 1B except
that the data is non-numeric and can therefore
be used as a program variable as entered in the

Listing 1D. ZX81 Simulation of DATA-READ
Statement Using a Variable Size Addressable
Array with New Data Addition.

05 REM LISTING 1D

10 GOTO 900

20 DIM A(LEN A$/3)

30 LET X=1

40 FOR J=1 TO LEN A$/3

50 LET Y=X+1

60 LET A(J)=VAL A$(X TO Y)
70 LET X=X+3

80 NEXT J

90 PRINT A(1)+A(2),A(3)+A(4),

A(5)*A(6) ,A(7)*A(8)

100 STOP
900 LET A$="05,10,15,20,"
901 LET B$="25,30,35,40,"
990 LET A$=A$+B$

999 GOTO 20

Listing 1E. ZX81 Simulation of DATA-READ
Statement Using Data Directly Addressable within
the Data String.

05 REM LISTING 1E
l0 LET A$-*05,10,15,20,"

20 PRINT VAL A$(1 TO 2)+VAL A$(4 TO 5),

VAL A$(7 TO 8)*VAL A$(10 TO 11)

Listing 2A. Conventional Basic
DATA-READ Program.

05 REM LISTING 2A

10 REM THIS PROGRAM WILL NOT WORK
IN ZX81 BASIC

20 DIM M$(12,3)

30 FOR N-1 TO 12

40 READ M$(N)

50 NEXT N

60 DATA "JAN","FEB","MAR","APR"

70 DATA "MAY" ,"JUN","JUL" ,"AUG"

80 DATAT ISSER OGT SNOV "DEC"

string without need for VAL function conver-
sion. It should be noted that the commas used
in the data string (line 10) are used only for
making the data readable. For computer pur-
poses, the commas as shown serve no purpose

Listing 2B. ZX81 Simulation of DATA-READ
Statement Using a Fixed Size Addressable Array
with Non-Numeric Data.

05 LISTING 28

10 LET D$="JAN,FEB,MAR,APR,
MAY ,JUN,JUL,AUG,
SEP,OCT,NOV,DEC,"

20 DIM M$(12,3)

3D CET Ke

40 FOR N-1 TO 12

50 LET Y=X+2

60 LET M$(N)=D$(X TO Y)

70 LET X=X+4

80 NEXT N

90 FOR N=1 TO 12

100 PRINT TAB (5*N)-3;M$(N)

110 NEXT N

Listing 2C. ZX81 Simulation of DATA-READ

Statement Using a Fixed Size Addressable Array

with Non-Numeric Data and Array Content Print-
out within Loop.

05 REM LISTING 2C

10 LET D$="JAN,FEB,MAR,APR,
MAY ,JUN,JUL , AUG,
SEP ,0CT,NOV,DEC,"

20 DIM M$(12,3)

30 LET .X=1

40 FOR N=1 TO 12

50 LET Y=X+2

60 LET M$(N)-D$(X TO Y)

70 PRINT "M$(";N;")-";M$(N)

80 LET X=X+4

90 NEXT N

and could be deleted. However, it is possible
to use such characters as data recognition
flags. In this case they would be required.
Listing 2C is the same program as Listing
2B except that the data array is printed out as

July/August 1983 © SYNC

the data array loop is executed. This program
routine is useful to display the contents of the
array but does not serve any program need. If
the print statement (line 70) is not executed,
the data will still be entered in the array as
program variables.

Listing 3A. Conventional Basic DATA-READ
vada n PERF. 0002 ee

05 LISTING 3A

10 DIM C(2)

20 LET C(1)=0

30 LET C(2)=0

40 READ A

50 IF A=-1 THEN 80

60 LET C(A)=C(A)+1

70 GOTO 40

80 PRINT C(1)C(2)
QOO DATA I SIS IE 212 1221515, 1,24

Program 3
Listing 3A is a program written in con-
ventional Basic using DATA-READ state-

Listing 3B. ZX81 Simulation of DATA-READ
Statement for Single-subscripted Variable Array
in Data Count Program.

05 LISTING 3B

10 DIM C(2)

20 LET C(1)=0

30 LET C(2)=0

BOE TICS" See Glia eect sd).
45 PRINT "LENGTH OF C$-";LEN C$,,

"DATA COUNT -";LEN C$/2

50 LET D=2

60 LET A=1

70 LET X=1

75 FOR N=A TO LEN C$/D

80 LET J=VAL C$(X)

85 LET C(J)=C(J)+1

90 LET X=X+2
100 NEXT N
110 PRINT

EZOP eer TCC.) 5 OC 2

130 PRINT C(1),C(2)

LENGTH OF C$-2f
DATA COUNT-1f

July/August 1983 ° SYNC

ments which cannot be executed on a ZX81
Computer.

Listing 3B is a counting routine using a
single-subscripted variable array. The array
diagram is shown in Figure 1. As shown by the
diagram, each data-set consists of one vari-
able, “A”. A running total is made of data-
sets equal in value to 1 or 2 which are ad-
dressed as variables C(1) and C(2) re-
spectively. Thus, in the data string (line 40)
there is a total of 20 characters. There are 10
data-sets, 7 of which are equal to 1, and 3 of
which are equal to 2. The arrangement of data
in the DATA STRING is as follows: 40 LET
C$=“‘A,A,A,etc”

Figure 1. Array Diagram for Listing 3B. —

Program 4

Listing 4A is a program written in con-
ventional Basic using DATA-READ state-
ments which cannot be executed on a ZX81
Computer.

Note: Lines are numbered as shown to save
memory for IK RAM.

Listing 4A. Conventional Basic DATA-READ

Program.

05 REM LISTING 4A

10::D1M-C( 253)

20 FOR Ys1 TO 3

JO FOR-Z21 T0. 3

40 LET C(Y,Z)=0

50 NEXT Y

60 NEXT Z

70 READ J,K

80 IF J=-1 THEN 110

90 LET C(J,K)=C(J,K)+1
100 GOTO 70
LIO-PRINE C(V1,1),6€C61,2),GCI 3)
I20 PEINT C021) Ce 2); 6 C£. 3)
1307 PRINT-C(3 1) ,C(352)46(3 52)

900: DATA. 1,2,1511,2,1,2,2,3,3, 31, 2,3,

1,3:1:3,2,1,351, 3,3,3;3,-1,-1

Listing 4B is a counting routine program
equivalent to Listing 4A using a double-
subscripted variable array. The array diagram
is shown in Figure 2. A running total of all
like data values are entered and counted in
the array addresses as shown in the array
diagram.

Listing 4B. ZX81 Simulation of DATA-READ
Statement for Double-Subscripted Variable Array
in Data Count Program.

REM LISTING 4B

DIM C(3,3)

FOR Y=1 TO 3

FOR Z=1 TO 3

LET C(Y,Z)=0

NEXT Z

NEXT Y

EF CS eo 221, 138 1425
CAPS Beer steer rt eS oy oe
3.94202 202 7

10 PRINT "DATA-SETS ="3LEN C$/4

20 LET J=1

30 FOR N=1 TO LEN C$/4

40 LET K=J+2

50 LET Y=VAL C$(J)

60 LET Z=VAL C$(k)

70 LET C(Y,Z)=C(Y,Z)+1

80 LET J=J+4

90 NEXT N

95 PRINT CCEA) ;EC1,2) CUT 23)

OG PRINT C4221) 9C(2, 21, 0(2 ;3)

OF PRINT CC3,1)50(3,; 2), 0603.3)

CO N O oc > C N r2

$3435
2r

DATA-SETS =13
1

Figure 2. Array Diagram for Listing 4B.

Each data-set consists of two data values (A
and B), a data separating comma and a closing
semi-colon. Thus in the data string (LINE 8)
there are 13 data-sets consisting of 4 string
characters each for a total string length of 52
characters (4 X 13 — 52). The data-set length
for program commands (line 10 & line 30) is
then LEN C$/4. The arrangement of data in
the DATA STRING is as follows: 8 LET
C$=“A,B;A,B;A,B; etc?"

Program 5

Listing 5A is a program written in con-
ventional Basic using DATA-READ state-
ments which cannot be executed on a ZX81
Computer.

Listing 5A. Conventional Basic DATA-READ
UC e nda an eua PFOS oido Esto re NEC

05 REM LISTING 5A

10 DIM X(2,3)

20 DIM Y(2,3)

30 FOR I=1 TO'2

40 FOR J= 1 TO 3

50 LET X(I,J)=0

60 LET Y(I,J)=0

70 NEXT J

80 NEXT I

90 READ A,B,C
100 IF A--1 THEN 180
110 IF A=1 THEN 150
120 LET X(1,B)=X(1,B)+1
130 LET X(2,C)=X(2,C)+1
140 GOTO 90
150 LET Y(1,B)=Y¥(1,B)+1
160-LET. Y(2,C)*Y(2,C)*1
170 GOTO 90
180 FOR I=1 TO 2
190 FOR J=1 TO 3
200 PRINT X(I,2),Y(I,J)

210 NEXT J
220 NEXT I
900 DATA 0,1,2
901 DATA 1,2,3

902 DATA -1,0,0

B Nar — er
F2 SY X) nc.

Listing 5B is a counting routine program
equivalent to listing 5A using double-sub-
scripted/multi-dimensional array. The array

Listing 5B. ZX81 Simulation of DATA-READ

Statement for Single-Subscripted/Multi-
Dimensional Variable Array in Data Count
Program.
REM LISTING 5B 1K RAM: FOR 1K MEMORY ENTER EACH OF THE

CEPTAS 0 1,25 1,2,3;"
DIM X(2,3)

DIM Y(2,3)

FOR Is1. TO 2

FOR J*1 TO 3

LET X(I,J)=0

LET Y(I,J)*0

Nds 70 NEXT J

80 NEXT I

TO LEN A$/6
LET S-VAL A$(L)

FOR J=1 TO 2

LET C=VAL A$(L+D+2)
IF S-1 THEN GOTO 27
LET X(J,C)=X(J,C)+41
GOTO 29

LET-Y (0, C)evrtas t)
LET D=D+2

NEXT J

LET D=0

LET L=L+6

NEXT N

eRe e Re eS xr xL
ON OWnre © MO DNA wm 4 WwW ne
=
rri
>x<
=d
—

n3
run

39 (ENTER)

N PO PR PO
O TREAT

39 (ENTER)

w W W w
N Q1 U Hn

Note for 16K RAM: For 16K memory fol-
low line 37 with lines 40 through 80. 1K
memory will accept 16K program but mem-
ory will fill with a report 4/60 before the entire
array is printed.

diagram is shown in Figure 3. A running total
of like data values are entered and counted in
the array addresses as shown in the Figure 3
matrix. Each data-set consists of three data
values (A,B,C), two separating commas and a
closing semi-colon. Thus in the data string
(line 2) there are 2 data-sets consisting of 6
string characters each for a total string length
of 12 characters (6 X 2 = 12). The arrange-
ment of data in the DATA STRING is as fol-
lows:

2 LET A$—'"A,B,C; A,B,C;A,B,C: etc"

Applying this method of simulating

40 FOR I-1 TO 2
50 FOR J=1 TO 3
60 PRINT X(I,J),Y(I,J)

RUN (ENTER)

FOLLOWING LINE 39 ENTERIES IN
SUCCESSION TO DISPLAY ALL MATRIX
VALUES OF THE ARRAY:

JS PRINTE XCI E ACA TIRT L2) 4962,38)
RUN (ENTER)

1 Ó |
9 g
6/39

39 -PRINT-X(1,2) ,X(2, 2) Y GE 29 Y 02429
RUN (ENTER)

BR I or roter m,

Note: For 16K RAM all line numbers may
be entered with addition of a trailing 0.

DATA-READ statements with the ZX81
should present no problem, provided the
demonstration programs are followed line by
line and the technique of string slicing is un-
derstood. The only major difficulty which
may be encountered is in actually slicing the
data from the string. For example, if a non-
numeri: character is included in data which is
fo be ccnverted to a numeric expression. such
as a comma, the program will not run. Of
course in this case an error code will be dis-
played (C/xx) upon execution of the program.
Sliced data can be checked for correctness,

Figure 3. Array Diagram for Listing 5B.

Y WAR ee errant Le. rs meen 2 MER Io s ns Se EE e rea s e S REMO GEO

"RITUUM TRE =
pa fra.n] valve [ren] nea) res) |

July/August 1983 © SYNC

CHANGE YOLIR
TIME xXx YS INCLATIR 19000 DISFLAY
TO FULL COLOLIF GRAPHIC:
with

ROLORWORKS

iL OH AT THE FEATURES f! II
e Plugs into ZX81/1000 (edge connector)

* User defined characters & graphics up to
256x192 pixels

¢ Module contains extension of basic
commands including: PAPER/INK/
BORDER/BIN/SPRITE/OUT/INP/etc.

¢ Latest technology with TMS9918 VDP
(32 sprite levels)

¢ Module contains it’s own memory

¢ All text will run on the color tv 5
for $i -AF 2m

KOLORWORKS COMES WITH A LIMITED WARRANTY ON PARTS AND WORKMANSHIP
USE YOUR KOLORWORKS IMMEDIATELY WITH A GAME CASSETTE FOR $9.95
This delightful game is designed for hours of fun using some of the color graphic capabilities of
KOLORWQRKS. The cassette also contains a short program to familiarize you with some of the
commands and graphics.

DOODOOOOOOOOGOOODOOOOOOOAOODOOOOOGOOOOOXOOODODOOOOOOOOOODOOOOOQOOOOOOoOoaGonoooooooooooooooooooodgooooooaoaadoaoooooaoaoaacbooadoaooooooa

Enjoy Game Fun With

CAAMWORRS

THE SOON TO BE RELEASED GAME MODULE
(proto-type stage) WILL OFFER SOUND, ROM
CARTRIDGES AND JOY STICK PORTS FOR
YOUR TS1000/Z2X81.

* THE SOUND will be of arcade game quality
which you can program for music, animals, trans-
portation (auto, train, airplane, etc.) and ma-
chine sounds.

* ROMCARTRIDGES will have up to 8K of ROM
using either 2716, 2732 or 2764 EPROMS. We
will have pre-programed cartridges and blank
cartridges which you can program. We will be
offering a service to burn EPROMS from your
cassettes. |

* JOY STICK PORTS will allow for the use of two “Atari” GGcompatible joy sticks.

SORRY PRICE IS NOT AVAILABLE AT THIS TIME! GAAMWORKS WILL BE AVAILABLE BY MAIL ORDER
FOR FURTHER INFORMATION, SEND $2.00 (Credited to Order).
At this time KOLORWORKS and GAAMWORKS is available only by mail order.
MAIL TO: BRAINCHILD COMPUTER WORKS, INC.

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PRICE QTY. AMOUNT
KOLORWORKS

Wi. residents add sales tax TAX Eu xu t
TOTAL

My Llcheck L] money order is enclosed ENCLOSED

Name

Street

City State Zip

Please allow six to eight weeks for processing. Thank you.

however, by simply executing a print com-
mand which displays the sliced data prior to
its use as a variable. The check is made during
the writing of the program by entering a
command to print the sliced data, running the
program, checking the data for accuracy, de-
leting the data print command and then pro-
ceeding with the writing of the remainder of
the program. For example, the following data
slicing check could be used for program List-
ing 1B after writing line 50:

Step 1: Enter new line.
55 PRINT AS(X TO Y)

Step 2: Enter new line.
56 PRINT VAL AS(X TO Y)

Step 3: RUN program.

Step 4: Check displayed data for accuracy.
Correct slice commands if necessary.

Step 5: Delete lines 55 and 56.

Step 6: Continue writing program.

Other Uses of This Technique

Use of the proposed ZX81 string statement
technique is not limited to simulating
DATA-READ statements. This method can
be used equally well to simulate other Basic
Language statements which cannot be exe-
cuted directly on the ZX81 Computer.

Program Listing 6A shows a Basic program
using an ON X GOTO N,N,N statement
which cannot be executed on the ZX81.

For the TS1000/ZX81

e MENU DRIVEN

Specify 16K or 64K RAM
LODAB and BDLS arc both:

e WRITTEN ENTIRELY IN MACHINE LANGUAGE
e SELF STARTING with automatic reset of ramtop
When both programs are loaded, vouaccess one menu from the other witha
single key. Both LODABand BDLS are accompanied by a manual;and for casy
instruction, cach program comes with a full demonstration program. |

Listing 6A. Conventional Basic ON X GOTO

n.n.n, Program.

05 REM LISTING 6A

10 LET X=INT (RND*6)+1

20 PRINT X;"£2IS THE RANDOM NUMBER"
30 PRINT

40 ON X GOTO 100,200,300,400,500,600
100 PRINT "THE RANDOM NUMBER IS 1"
150 GOTO 700
200 PRINT "THE RANDOM NUMBER IS 2"
250 GOTO 700

300 PRINT "THE RANDOM NUMBER IS 3"
350 GOTO 700

400 PRINT "THE RANDOM NUMBER IS 4"
450 GOTO 700

500 PRINT "THE RANDOM NUMBER IS 5"
550 GOTO 700

600 PRINT "THE RANDOM NUMBER IS 6"
700 PRINT "END"

X IS THE RANDOM NUMBER

THE RANDOM NUMBER IS X
END

USED INDIVIDUALLY, EACH PROGRAM IS A STRONG AND
USEFUL TOOL. COMBINED, YOU HAVE ONE POWERFUL PROGRAM

Renumber your entire BASIC
program or renumber a block of
lines. Store a BASIC program for
later recall; or merge two or more
BASIC programs. Keep track of
your memory requirements with
a memory chart of the BASIC
program area. LODAB will occupy
1450 bytes.

LODAB 51299
BDLS 1290
BOTH for 52209

California residents add 6'5?o tax.
Outside of Continental U.S. add 91%,
These prices include shipping & handling.

FOR EDITING & HANDLING YOUR OWN BASIC PROGRAMS.

LODAB © BDLS

personal check or money order to:

The Ultimate Blackwood

At the touch of a key, your BASIC
program listing will scroll up the
screen. Blocks of lines may be
deleted or copied. This is an ideal
method for editing your BASIC
programs. BDLSis relocatable, and
will occupy 44K.

For IMMEDIATE delivery, send a

PO Box 7127
Santa Cruz. California 95061

Listing 6B. ZX81 Simulation of ON X GOTO

n,n,n Statement.

05 REM LISTING 6B
10 LET X=INT (RND*6)+1

20 PRINT X;"4IS THE RANDOM NUMBER"
30 PRINT

40 LET A$="100,200,300,400,500,600,"
50 LET L=1 |

55 FOR N=1 TO LEN A$/4

60 LET S=VAL A$(L TO L+2)

65 PRINT "CYCLE NUMBER£Z";N

70 IF N=X THEN GOTO S

80 LET L=L+4

90 NEXT N

100 PRINT "THE RANDOM NUMBER IS 1"
150 GOTO 700

200 PRINT "THE RANDOM NUMBER IS 2"
250 GOTO 700

300 PRINT "THE RANDOM NUMBER IS 3"
350 GOTO 700

400 PRINT "THE RANDOM NUMBER IS 4"
450 GOTO 700

500 PRINT "THE RANDOM NUMBER IS 5"
550 GOTO 700

600 PRINT "THE RANDOM NUMBER IS 6"
700 PRINT "END"

Note: To have program recycle enter the
following lines:

710 PAUSE 125
rL CES
730 GOTO 10

X IS THE RANDOM NUMBER.
CYCLE NUMBER N

THE RANDOM NUMBER IS X
END
0/700

Listing 6B, however, shows the equivalent
program structured for execution on the ZX81
using the same string statement technique
previously described. The program generates
a random number which is compared to the
value of the first character of a data-set in the
data string (line 40). When the string charac-
ter value is read which equals the value of the
random number, the remainder of the selected
data set is also read to provide a GOTO line
address. That line address then executes a
print command which identifies the value of
the random number. It should be noted that
although Listing 6B is to demonstrate an ON
X GOTO N,N statement, line 70 could exe-
cute any ZX81 command (PRINT, STOP,
LET, etc).

It appears, then, that the ZX81 has lots of
Basic capability if you can use your pro-
gramming imagination and just keep
$TRINGING ALONG WITH THE ZX81. Fg

July/August 1983 * SYNC

DISCOVER THE MAGAZINE

THAT HELPED LAUNCH

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Automatic Video Game/TV Antenna Switching
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Polish Your
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Mcintosh MA-6200 integrated Stereo Amplifier
Teknika 19" Color TV Monitor

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uuum me» diee qui iam meten quain qM Wed E Gane dei spei quia Masi dui cita) wing dumis duce didi di qucm. NM Mau

—————————————————————»———————RRERR

For most of us, the anticipation of be-
ing able to write extended programs
when we first plugged in our new 16K
RAM pack was soon somewhat tem-
pered by the waiting out of the monot-
onous count at the end of every SAVE
and LOAD. Also, functions such as CLS
and NEW take much longer.

Without connecting and disconnect-
ing the RAM pack, the advantages of a
smaller RAM may easily be regained by
changing the address of RAMTOP for
any program which requires less than
31K RAM to RUN. Simply set
RAMTOP below this limit by entering
as direct commands (without line num-
bers) one of the following sets, with the

Robert D. Hartung, PO Box 125, Palmyra, NY
14522.

SUB COMMANDER €,

The torpedo tubes are loaded.
In front of them is an enemy
You order
safe below
Finally
But did they
No time to
look, sonar reports a destroyer
about to make a depth-charge run.
Everyone on your ship awaits your

aircraft carrier.
"EIREX2"- ana’ “DLVE
the surface you wait.
the torpedoes hit.
sink the carrier?

next command.

Can you survive to become an
admiral in the Bronze Star Navy?
You give all the commands, The
fate of your ship and crew is
entirely in your hands and mind.

16K

All software designed for the

T/S 1000 and ZX81

16K RAM plugged in:
For 1K (17408): For 2K (18432)
POKE 16388,0 POKE 16388,0
POKE 16389,68 POKE 16389,72
NEW NEW

For 3K (19710)
POKE 16388, 254
POKE 16389,76
NEW

When you have set the RAMTOP ad-
dress to 19710 (which was POKEd in as
76*256--254), your computor will be-
have as though it has only 3.1K RAM.
(These addresses are valid only for 8K
ROM). You can also LOAD programs
into this 3.1K which have previously
been SAVEd to tape in 16K, provided
they do not exceed the RAM limit as it

16K

$15.00 16K

FOOTBALL PREDICTOR II

Know who will win any pro game
before it is played.
uses Statistics you update weekly
in order to predict the potential
of each team and the expected
final score.

Can you help little ZT find his
way home? This hidden maze game
has four levels of play and is
different each time it is played.
A game for the whole family to
play and enjoy.

| RUNning with Reduced RAM Robert D. Hartung

is now set. They may then be SAVE
back to tape in 3K, saving time and wear
and tear on your recorder—and your pa-
tience. The reduced RAM will remain in
effect until the computor is powered-
down or RAMTOP is reset.

If tape listing does not LOAD because
it was SAVEd with strings or variables
or DIMs defined in memory, it might fit
into 3.1K if cleared before the SAVE to
tape. Restore the 16K RAM by power-
down and then LOAD the program.
CLEAR and then SAVE it back to tape
again in 16K. Reset RAMTOP to 19710
and try to LOAD it back. If you suc-
ceed, you may now SAVE it to tape in
3K RAM, but it will require 16K when
it is LOADed back if you want to RUN
it.

To keep track of the reduced number
of bytes remaining during the listing of a

The program

(includes USFL)

$10.00

$ 7.00

BRONZE STAR SOFTWARE

Prices include postage and

handling charges

Dealer inquiries invited

P, Oe BOX 265

Chicago Ridge, IL

60415

new program, first set RAMTOP to
19710 by POKE 16388,254 and EN-
TER; POKE 16389,76 and ENTER;
and NEW and ENTER. Then enter
these lines (with the 16K RAM pack in
place):

1 DIM A(16)

2 FOR N=1 TO 16

3 INPUT A(N)

4 PRINT AN); “HHH”;
5 POKE 32751 4- N,A(N)
6 NEXT N

RUN and INPUT the following val-
ues, reading horizontally:

42 28 64 205 203 14
229-193. 33 20 0 237
56: 229. 193. 201

After checking the printout, add the
following lines (changing line 1 to the
USR command):

1 PRINT USR 32752;"3: BYTES
REMAINING"

7 STOP

8 SAVE "BYTES"

9 GOTO 2

SAVE to tape for future use with
GOTO 8. After the SAVE, the display

should show the table of INPUTs. Now
delete all the lines except line 1 and
RUN. The display should show 3101
BYTES REMAINING. The routine is
resident above RAMTOP and will not
be affected by RUN, CLEAR, NEW,
SAVE, or LOAD as long as RAMTOP
is not reset above 32752 or the computer
is not powered-down.

RAMTOP must be set to 32752 or
less before “BYTES” is LOADed back
from tape, and the machine code values
will then be automatically POKEd in
when the LOAD is completed. (They are
not SAVEd to tape as they exist above
RAMTOP but are reproduced from the
variables stored in DIM A(16). Line 1
will have to be reentered after the
LOAD of a listing other than “BYTES”
or may be used as a direct command
(without a line number) at any time dur-
ing the listing of a new program as long
as the "BYTES" routine is resident
above RAMTOP.

The actual bytes remaining will vary
slightly from the number displayed but
when used for most practical purposes,
such as noting the effects of byte-saving
techniques, the routine can be very help-
ful. RAMTOP must be set to 32752 ad-
dress by POKE 16388,240 and ENTER,
POKE 16389,127 and ENTER; NEW
and ENTER for 16K. "n

Read This Fir

Before entering the programs it in T
issue, readers should note the follo

ing:

for using a given program are sh

at the top of the first page of the a

cle. Observe these carefully.

The ROM and RAM requiren

NEWLINE and ENTER are us

interchangeably.

A letter after a number shows t

type: b for binary; d for decimal;
hexadecimal.

In PRINT statements:

#: Enter a necessary space.

A (32): Use the graphic chara
on the A key 32 times. The unde
means use the graphic on that ke

A: The overline means use t

in inverse.

INPUT: An underlined word fe
on the keyboard should be ent
from the keyboard, not spelled o1
the keyword will not ENT
THEN, the keyword you want, b
space and delete THEN, cont
entering the line. This memory sa
technique may be disregarded if
have enough RAM.

for
Timex Sinclair 1000
Sinclair ZX80/ZX81

July/August 1983 ° SYNC

FOR TOTAL
CONTROL

of Your Timex Sinclair

. by David A. Lien

questions.

——--X— 9

Please send

Total Enclosed

The Only Programming Manual You'll Need

Learning Timex Sinclair BASIC, Dr. David Lien's new, 350-page,
comprehensive manual for the Timex Sinclair 1000 and Sinclair
ZX80/ZX81, is the one book that answers all your programming

Learning Timex Sinclair BASIC's simple, step-by-step instructions
make it ideal for the classroom. And it's a must for all Timex
Sinclair owners, especially first-time computer users. Don't miss
this opportunity to learn from a proven teacher of BASIC how to
write your own custom software.

Don't waste time with other confusing, incomplete programming
guides — order Learning Timex Sinclair BASIC now. Fill out the
coupon or call our 24-hour order line at 800-854-6505, in California
call 619-588-0996 (8:00 a.m. - 5:00 p.m.).

30-Day Money Back Guarantee

If you're not totally satisfied with this book for any reason, return
it to Compusoft in salable condition within 30 days for a full refund.

CompuSoft® Publishing

535 Broadway, Dept. # 070783

El Cajon, CA 92021

LJ A GRE AGE BABS EE LI LI I | I LIII ZB. b
copies of Learning Timex Sinclair BASIC at

$14.95 each (Calif. residents add 6%) plus $1.65 shipping and

handling per book within the U.S. Foreign orders, include $2.50
surface shipping and handling per book.

Name
Address

City/State/Zip

[] Check [] Visa

E E T TU T D

8 Signature

[] MasterCard

en OT See
Expiration Date

Please allow 4 to 6 weeks
for delivery. 070783

sii

NLIII ELebeLLLLuL

Hardware Review

The Votem Lawrence A. Kelly

Votem. Kit: $39.95; assembled and tested:
$59.95; plus $3 s&h. Down East Com-
puters, PO Box 3096, Greenville, NC
27834.

The Votem, to play on James J. Carr’s
book Digital Interfacing to an Analog
World (Tab Books, Summit, PA. 1978), is
an analog interface to Sinclair’s digital
world.

Analog/Digital Conversion

Analog (related to analogous) refers to
relationships by ratios. The analog device
relates numbers to a turn on a wheel such
as our rapidly disappearing analog wrist-
watch; to the movement of a rod or shaft
such as the slide rule; or to continuously
changing voltages or currents such as in
an electronic analog computer.

The electronic digital computer, of
course, also works on voltages but in
discrete packages or digits as in the digital
wrist-watch with the liquid crystalline dis-
play. Digital computers, unlike the watch-
es, do not count in decimal (0-9) in their
digits, but rather use a bistable digit which
is voltage or no voltage, in other words,
on or off, 1 or 0, true or false.

What Carr is driving at in the title of
his book is that most of the devices we
use to measure and control things are
analog in nature. Transducers convert
physical energy such as strain, thermal
energy, or light energy into electrical
energy in a continuously changing voltage
or current related to the amount of ener-
gy, yes, its analog. In order to control
things, voltages or currents have to be
output.

The Votem is a device which can
measure external events relating Analog/

Lawrence A. Kelly, Ph.D., 28 Countrywood Dr.,
Morris Plains, NJ 07950.

xpand the cognitive
horizons of your
TS1000 to the
real world.

Digital (A/D), but it does not go the other
way for control, Digital/Analog (D/A).

A/D by the Votem

How does the Votem manage the mar-
riage between the analog and digital
worlds? It takes advantage of the fact
that the Z80 processor uses a crystal to
generate a pulse at a given frequency.
This produces a clock to take care of the
timing of events in the operating cycle of
the machine.

The heart of the Votem is a voltage to
frequency converter (V/F, AD537JH).
The V/F relates the frequency of the
Sinclair clock to voltage applied to the
external connection of the Votem. This is
done via a machine language program
(provided in the manual) which converts
the clock pulses to a count/volt. Basic
programs can then convert the voltage to
something meaningful such as the temper-
ature at the end of the probe and display
it periodically on the TV screen.

Temperature Measurement

The Votem comes with a temperature
probe of the resistance type with the
change in resistance proportional to temp-
erature. By calibrating this probe to 0 C
(ice) and 100 C (boiling water) one can
display on the screen the room tempera-
ture using a Basic program. The calibra-
tion is all important in the final accuracy
of the result because the software uses
these calibration factors in the calcu-

lations. Since clock frequencies can vary
from computer to computer, accuracy is
to a certain extent in the hands of the
user.

The Votem can interface with position-
al devices (e.g., joysticks), photocells (e.g.,
spectrophotometers), and virtually any-
thing with an output voltage in the 0-1V
range (e.g., ionization detectors).

Tape Load Circuit (Earphone)

The Votem connects via the tape ear-
phone port and thereby leaves the expan-
sion port of the computer free. A RAM
pack or Byte-Back’s BB1 control module,
or both can still be used. The BB1 device
can be programmed to turn on relays
which can switch on 110VAC items such
as lights or coffee makers. The ZX/TS
owner has an opportunity to do some
practical things not previously possible.

Getting the most mileage possible out
of the device, the frugal designer also
employed unused portions of the circuitry
to condition the tape signal to improve
LOADing, providing audio output of the
signal and an LED which glows during
the LOAD. We found this feature to be
quite useful. Those with LOADing prob-
lems might find the the Votem a useful
addition for this reason only.

With just three integrated circuits—
only one of which is in a DIP, it is a
relatively easy kit to assemble, for those
who like to become intimately involved.

For those who want to make the most
out of a Votem/Sinclair combination
Carr’s book is recommended reading.

The Votem is probably not for those
who cannot quite remember who Ohm
was, or which parameter goes on top and
bottom in his equation. But for those who
do and would like to expand the cognitive
horizons of their computers the Votem is
a must.

July/August 1983 © SYNC

Timex Developments Paul Grosjean

The printer is out. Three new machines
are about to hit the market. Another price
reduction is made. These are among the
recent developments in the Timex Sinclair
computer field.

Timex Sinclair 1000 for $49.95

In our last issue we reported that Timex
Computer Corporation had reduced the
suggested retail price for the TS1000 to
$69.95. On April 28, 1983, Timex an-
nounced a further reduction to $49.95.
Remember the breakthrough of the origi-
nal ZX80 for $199.95?

eau

Timex Sinclair 1500 for $79.95

On May 17 Timex announced the intro-
duction of the Timex Sinclair 1500, an
enhanced version of the TS1000. Shipment
is expected to begin in July.

The most obvious enhancement is a new
styled case supporting a full movement
keyboard instead of the familiar mem-
brane keyboard. The 40 keys have the
same layout, commands, functions, graph-
ics, and characters as the TS1000. The
second major enhancement is that the on- | -— r—“C—O_C_O—_
board RAM has been increased to 16K Photo 1. The Timex Sinclair 1500.

and can be expanded to 32K by the TS1016
16K RAM pack.

The TS1500 is compatible with all
TS1000 peripherals and software. Stand-
ard cassette recorders are used for saving
and loading, but the new instant-load soft-
ware cartridges being developed by Timex
will plug directly into the computer. These
palm-sized cartridges are expected to cost
from $12.95 to $29.95 and to be available
in August.

Timex Sinclair 2000 Series

Timex also announced on May 17 that
two computers in the 2000 series would be
available to retailers in August. One with
72K RAM is priced at $199.95; the other
with 40K RAM at $149.95. The video
display can be output to most color and
black-and-white TV sets as well as to a
monitor.

The keyboard has 40 moveable keys
arranged in typewriter format with upper
and lower case letters, repeat key option
for all keys, 16 built-in graphics characters,
and 21 user-programmable graphics char-
" acters. Each key performs up to six

Photo 2. The Timex Sinclair 2048. functions. Most of the functions, com-

Continued on page 60.
July/August 1983 9 SYNC 77

Hardware Review

Memopak High Resolution Graphics Module

John Herriott

Memopak HRG Module. $99.95 plus page,” how to set the switches and remove A short program illustrates setting para-
$4.95 s&h. From Memotech Corp., 7550 the small jumper switch for full use of the meter V and calling a routine contained
W. Yale Ave., Denver, CO 80227. i 64K. in the 2K EPROM. The result is a black

The Memopak High Resolution Graph-
ics Module, in dull black matching the

computer, fits in between the Memopak | 2 ~n D
parallel printer interface and the 64K MEMOPAK HRG " » u—-——— o
memory module. Velcro tape or double NPR ARS POM SR Dee DAES CWO (ae SO S APA te eA RINT ee ACE RN CC SE DUO

sided adhesive tape comes with each unit
to ensure a wobble-free set-up.

The 18 page instruction booklet, which | — HSSeA UE V Ae E ESTE FAON react: Rees PET RAE NCEE IN GOLA
serves only to whet the appetite, begins NR MC E dde ee CE e Uy ES — | |
with a brief but lucid account of a “video LEA EDU: (Na MARR prae ANE

ee: | | ' : 1 whos b= ie fm bok Bm B B d - TIT
John Herriott, 143 LeMarchant Rd., St. John's, : i. li un a L HARB ARORE.
Nfld, Canada A1C 2H3.

Instrumentation & Con MOL cov

ANALOG INTERFACE BOARD

8 channels A/D + 8 channels D/A. 1.6uS A/D convert time. Uses
BASIC or machine code. Does NOT need Buffered Buss. Includes
parts for piggyback to ZX/TS & RAM. Many jumper and

switch selectable options. Has features which allow

easy interfacing to other micros. Tested on ZX/TS,

Apple, TRS-80, CBM 64, others. Manual w/software.

You must see spec sheets to appreciate this board.

$195.

BUFFERED BUSS-
DEVELOPMENT BOARD:kit $65. MAN en
bare board $ 35. wr connector ann MANUAL E

APPLICATIONS BOOK FOR ‘BUSS’: Plans& programs for 8255 port & EPROM PGR. 40 pgs. $1 O.

CURE CRASH = MODULATOR
CON N ECTORS Prosiems! /— UHF SEE ARTICLE IN
epic to fit ZX/TS & switch to ch. 33 S JAN SYNC.
peripherals. * REMOVES INTERFERENCE
< ASSEMBLY w/8" cable $18. FROM YOUR TV DISPLAY !

You can add more | This modulator is soldered on the com-
connectors to the assembly puters circuit board in place of the
or create your own VHF modulator. Requires soldering
from parts: skills. We install for $10 extra plus our
Female connector $3 shipping charge. Satisfaction guar-

to ZX/TS " anteed or we will refund you on return

Male connector to of a working modulator.

peripherals

or call.
TERMS: Please add $3 for shipping and handling. California residents 301 16 th Ave d
please add 62% tax. To order, send check or money order or call for C.O.D. San Francisc O, CA 94118 (415) 752 6294

N OK
FREE CATALOG Explaining our products and applications. Write o m p U te r ( 9 n t n U U m

78 July/August 1983 ° SYNC

screen with white-lettered MEMOTECH.
The small black button on the right side
returns the computer to Basic.

Armed with this experience, one can
follow the explanation of how the HRG
works, the nature of a pixel, a “video
page," and the bit and byte summaries.

Thirty subroutines can be called from
address 8192. There are five varieties of
routines: Page: manipulation and prep-
aration of displays. Block: rolling and
scrolling the display in four directions.
Character: sketching, unsketching,
inverse-sketching of user-defined char-
acters. SINCH: plots ZX81-defined char-
acters. Line routines draw and wipe out
lines and fill in areas of your masterpieces.
PLOT and UNPLOT function as on the
ZX81 except that the result is a tiny spot
instead of a big, square blob. 47616 of
these spots or pixels are possible; 192
vertical and 248 horizontal.

SKETCH allows you to design your
own characters by setting each bit:

LET C$=“10101:”
gives you a line. The * can be used instead
of 0 for the sake of clarity. By astute use
of the NESW direction commands one
can produce a neat cross, thus: |
LET C$-"1***1NE1*1NEINW1*1NWI1*

mi.

My efforts to produce a Russian character
set (well, one letter actually) developed
an interesting array of Devenagri and
Coptic symbols at first!

Listing 1.
5 REM "L/BOX" 115 LET Y=20
10 LET V=40000 120 GOSUB 9990

20 LETZ$="STARCH" 122 REM MID/HORIZ
30 RAND USR 8192 125 LET X=60+I

35 LET Z$s"PLOT" 130 LET Y=45
40-FOR I1s1 TO 50 135 GOSUB 9990

50 LET X =10 137 REM HI/HORIZ
55 LETY-20«I 140 LET X=60+I
58 REM VERTICAL/L 145 LET Y-95

60 GOSUB 9990 150 GOSUB 9990
63 REM LOW/DIAG 153 REM DIAG/R
65 LET X=10+I 160 LET X=60+I
70 LET Y-20«I/2 165 LET Y=20+I/2
75 GOSUB 9990 170 GOSUB 9990
77 REM HI/DIAG 175 LET X«110

80 LET X=10+I 180 LET Y=45+I
85 LET Y=70+I/2 185 GOSUB 9990
90 GOSUB 9990 220 LET X=60+I
92 REM MID/VERT 225 LET Y-454I
95 LET X-60 230 GOSUB 9990
100 LET Y=45+I 500 NEXT I

105 GOSUB 9990
108 REM LOW/HORIZ 9990 RAND USR 8192
110 LET Xz10-«I 9995 RETURN

Line notes:

20: Macro page command; combines
Start, Clear, HRG. |

60: The call is assigned to a subroutine.

Listing 1 uses PLOT to produce a rep-
resentation of a portion of a box with
each line being drawn simultaneously.
Although the program might appear un-
wieldy because of the GOSUBS, one can
watch each of the lines add its bit in the
proper order. Adding line 37 FAST
reduces the time the program takes from
65 seconds to 13, but the joy of watching
the process is lost! Any use of FAST
mode should be countermanded with a
SLOW. The instructions say that one can
break into a program in FAST mode by
entering SLOW and then pressing the
Basic RETURN button. However, I have
had no success with this, and so I take the
obvious precaution.

“LAUNCH”, one of the line routines,
fires black lines up the screen. A neat
routine to change the firing position holds
all kinds of game possibilities.

“Draw It” by Robert Boynton (SYNC
2:4) or “Draw and Store” by James J.
Hollandsworth (SYNC 2:6) can be suit-
ably modifed to produce a fairly fine-line
sketch-pad.

With the ability to pack pages of graph-
ics into a Basic string which can be
SAVEd and unpacked later for display,
the Memopak HRG is a useful addition
to a ZX/TS set up. a”

SPECTRUM

IS COMING SOON

KNOCK DOWN

LEARNING BARRIERS
Enter the World of MACHINE LANGUAGE

SINCLAIR'S much heralded colour computer in
16K and 48K versions with sound, professional key-
board and high speed load will be known as the Timex
Sinclair 2000 in North America.

e Qur prices are as follows
IBN Luz. $144.95 48K 5... vis $195.95

INCLUDING DELIVERY by insured parcel post. N.Y residents add
796 sales tax. Canadians add 2596 (U.S. funds) for customs clearance,
F.S.T. and delivery by registered mall.
Delivery is expected in late July and supplies will be
tight. We are asking for a deposit of $25 to secure your
positión at the front of the waiting list. You will be
notified to send the balance of your payment when we
receive Stock.

Order now to avoid a long delay in getting in on the
hottest computer bargain since the ZX-81.

We also offer, at the lowest pfices in the country, all
Timex Sinclair hardware and software.

PMOL OUS oe ess Pe dE $89.95
16K Memory Module ............ $45.95
Stabilizer Pad (a must) ........... $6.95

Postage Extra.
Please send cheque, money order or VISA number
and expiry date to:

STREAM COMPUTERS P.O. Box 784 Lewiston,
N.Y. 14092 === 416-960-2488

July/August 1983 © SYNC

With Greater Ease

Learn How Your Sinclair Works
with MEMORY SCOPE

An innovative development in memory control has brought forth
MEMORY SCOPE, a new program that makes understanding your
computer and learning machine language much easier.

MEMORY SCOPE is actually two programs in one. One is a full-
screen machine programming editor with unique features that make
entering, revising, and running machine code programs a simpler
task. The other is an exploratory scope that gives a “live” view of any
section of memory through a full-screen window that can be rapidly
scrolled or positioned.

MEMORY SCOPE can be installed with other programs (space per-
mitting) to learn more about them or make revisions.

An ideal learning environment for venturesome beginners or an
indispensable program development tool for experts.

Never before has a program provided so much potential for
discovery, with so many powerful programming features, at such a
modest price.

Complete instructions included with many instructional ex-
amples to get you started.

Written in Machine Code
For TS1000/ZX81 with 16K

On Cassette for $7.95 add $1.50 for shipping

BONNIE & CLYDE SOFTWARE
P.O. Box 13651
Albany, N.Y. 12212

Timex Developments, continued...

mands, characters of the TS1000 are re-
tained and in the same places, but a few
have been moved, e.g., the number keys
have the same character placement as the
standard typewriter keyboards. New func-
tions have been added to handle the
increased capabilities of the computer.
The Basic has also been expanded, most
notably with READ, DATA, and
RESTORE.

Probably the chief difference from the
1000 that users have been anticipating is

the high resolution color capability. The
features include eight colors; control of
the foreground, background, and border
areas; a flash command; and a brightness
control. The display area consists of 24
lines with up to 64 characters each. The
high resolution display has 256 dots hori-
zontally and 192 vertically which can be
individually addressed.

A fully programmable sound capability
is provided by a built-in speaker with a
range of 10 octaves and 130 semitones.

Directory of Suppliers

The BEEP command allows setting the
pitch and duration of sounds. Users who
want to compose music will be able to do
so on the computer.

Although the 2000 series continues to
use cassette saving and loading, an exten-
sive software line will also be available on
the new mini-cartridges that plug directly
into the computer. Another feature is a
built-in real time clock. This will allow the
user to run real time programs and coordi-
nate with appliances.

Ed. — This Directory supplements the list in our Buyer s

Guide Issue. A few suppliers are repeated because of

Aardvark
2352 S. Commerce
Walled Lake, MI 48088

Acts Audio, Inc.

70 W. Illiana Ave.

Orlando, FL 32806
(305) 423-0338

Air Capitol Software
PO Box 12051
Wichita, KS 67277

American Micro Products, Inc.
705 N. Bowser, Suite 121
Richardson, TX 75081

(214) 238-1815

A. + Associates
175 5th Ave., Suite 3119
New York, NY 10010

Applied Software Development
Association, Inc.

Rt. 1, Box 330

Parkin, AR 72373-0330

Asia Tsusho Co., Ltd.
7-6, 1-chome
Soto-Kanda, Chiyoda-ku
Tokyo, Japan

A, T&A Comp-U-Ware
2712 G St.
Middletown, OH 45042

Audio Vision
1279 N. Normandie
Los Angeles, CA 90027

Biocal Software
340 Cypress Drive
Fairfax, CA 94930

Note: Minimum order: $10.
Cassettes: $5; listings: 6/$ 10. All
programs 16K RAM unless
noted otherwise.

the products carried over or new product listings.

Bomis Prendin Software

PO Box 28550
Washington, DC 20005

Note: SASE with orders.

Charles J. Bonner
PO Box 9179
Norfolk, VA 23505

Bonnie & Clyde Software

PO Box 13651
Albany, NY 12212

Bronze Star Software
PO Box 265
Chicago Rdg, IL 60415

Bug-Byte Software
100 The Albany
Old Hall Street
Liverpool

U.K. L3 9EP

Business Management
Specialists

PO Box 4073

Dearborn, MI 48126

Robert Cannon
309 N. Broadway
Yonkers, NY 10701

Circle Chess Journal
Box 63
Des Plaines, IL 60017

Cobra Technology, Ltd.

378 Caledonian Rd.
Islington
London, U.K. N1 1DY

John Richard Coffey
PO Box 448
Scottsburg, IN 47170

Compu-Pak
2615 Waugh Dr., Suite 295
Houston, TX 77006

(713) 523-3691

Computer Add Ons
7-9 Thane Works
Thane Villas
London, U.K. N7

Computer Assistance Inc.

PO Box 3402

Cincinnati, OH 45201
(513) 381-8778

Computer Practice
Keyboard Co.

616 9th St.

Union City, NJ 07087

Computer Software Associates
50 Teed Drive
Randolph, MA 02368

The Computer Trader
PO Box 20976
San Diego, CA 92120

Computronics
Box 117
Okemos, MI 48864

Compuwiz Software

PO Box 390078

Mountain View, CA 94039
(415) 961-7204

CRC Software

2901 Auburn Rd.

Auburn Hgts., MI 48057
(313) 852-3711

C-20 Magazine
PO Box 3801
Wichita, KS 67201-3801

Curry Computer
5344 W. Banff Ln.
Glendale, AZ 85306

Datametrics
Trout Rd., West Drayton
Middlesex, U.K.

Ph: West Drayton 43168

Daydesign
790 E. Big Beaver Rd.
Troy, MI 48084

Discount Software

320 E. 59th St.

New York, NY 10022
(212) 486-0980

A. Doty
PO Box 11023
Ferguson, MO 63135

Dynamic Designs
PO Box 872
Norco, CA 91760

Edson Electronics
PO Box 151211
Tampa, FL 33684

Electronic Specialists, Inc.
171 S. Main St.
Natick, MA 01760

Emvee Software
10 Mythrop Rd.
Lytham, Lancashire
U.K. EY8 43D

Ener-Z Co.
PO Box 635
Ft. Washington, PA 19034

Ezra Group Il

PO Box 5222
San Diego, CA 92105

July/August 1983 * SYNC

Felix Software (Dept SC1)
19 Leighton Ave.
Pinner, U.K. HA5 3BW

Bob Fingerle
39639 Embarcadero Terr.
Fremont, CA 94538

Fisher-Marriott Software

9c Abbey Hill

Kenilworth

Warwickshire, U.K. CV8 1LW
(0926) 511254

Florida Creations
PO Box 16422
Jacksonville, FL 32245

The Forth Dimension

1451 N. Union St.

Middletown, PA 17057
(717) 944-6000

The Fourth Design
PO Box 1406
Niagara Falls, NY 14302

Frog Software
PO Box 95
Glenmont, NY 12077

GCM Electronics

PO Box 6152

Ft. Smith, AR 72906
(501) 646-2100

General Systems Consulting
2312 Rolling Rock Dr.
Conley, GA 30027

N. J. Gipson
43 Penn Dr., RD 6
Coatsville, PA 19320

Gladstone Electronics
1585 Kenmore Ave.
Buffalo, NY 14217

Rois R. Harder

995 Shakespeare Ave.
North Vancouver, B.C.
Canada V7K 1E7

L. Harmon
4909 Clearlake Dr.
Metairie, LA 70002

Hawg Wild Software
PO Box 7668
Little Rock, AR 72217

Haymarket Software
PO Box 14026
Jacksonville, FL 32238

Hewson Consultants
60A St. Mary’s St.
Wallingford, Oxon
U.K. OX10 OEL

Home Applications
2169 Hikido Dr.
San Jose, CA 95131

Intercomputer, Inc.
PO Box 90, Prudential Center
Boston, MA 02199

July/August 1983 ° SYNC

J K Audio
PO Box 3295
Escondido, CA 92025-0580

Kamel Technology
2802 W. Bay Area Blvd., #2106
Webster, TX 77598

Kabre Electronics

17880 Los Alamos

Fountain Valley, CA 92708
(714) 963-3118

Ksoft
845 Wellner Rd.
Naperville, IL 60540

Laminar Inc.
1514 Fairview, Box 12332 (S)
Columbus, OH 43212

Larsoft Software
PO Box 255
Waterloo, IL 62298

Laserscan Electronics
Corporation

2305 Broadway

Riviera Beach, FL 33404
(305) 842-4255

Markel Software
PO Box 2392
Secaucus, NJ 07094-0992

M. H. Marks Enterprises

315 Thornberry Ct.

Pittsburgh, PA 15237
(412) 486-1694

Martech Games

9 Dillingburgh Rd.
Eastbourne

East Sussex, U.K.

MAV Microproducts
PO Box 31256
Seattle, WA 98103

Memory Master
PO Box 774
Barnegat, NJ 08005

Memotech Corporation
7550 W. Yale Ave.
Denver, CO 80227
(303) 986-1516
Note: See Memotech's ads in
this issue for price update.

Microcomputers Plus, Inc.

349 E. Main St.

Galesburg, IL 61401
(309) 342-9572

Micro Developments
Box 1140

2000 Center St.
Berkeley, CA 94704

Micrografix
306 Double Tree
Lewisville, TX 75067

MicroSync Software
7440 N. Rockwell
Chicago, IL 60645

SIMPLEX SOFTWARE
INTRODUCES A NEW LINE OF QUALITY, AFFORDABLE

AND RELIABLE 16K CASSETTE SOFTWARE FOR
ZX81 and TIMEX/SINCLAIR 1000.

Introductory Prices Good Until 8/31/83

RECREATIONAL-PAC: .....................- $195 ....$9.95
1. BIORHYTHMS - Computes and plots 4 weeks of your bio-
rhythms
2. ANIMALS - Popular artifical intelligence learning game
PRE PI OS LL Ld canoe oot a et siye raus $1495 ....$9.95
1. COMP-U-SKETCH - Computerized version of popular
ETCH-A-SKETCH toy
2. MICRO ORGAN - 4 octave organ music through your TV
3. KALEIDOSCREEN - TV screen becomes a computerized ka-

leidoscope
EBIUPAD e E gene tr thy Sateen di $9.95 ....$7.95
1. MATH DRILLS - 4 programs with 4 to 5 levels and score-
board

2. COMPUTER AIDED INSTRUCTION - General purpose educa-
tional program

MATHSTAT-PAC: Lees isiliesss $10-95 ....$8.95
1. STATISTICS - Computes mean, variance and standard

deviation

2. LINEAR REGRESSION - Computes regression coefficients
and displays equation

3. VECTOR MATH - Adds two vectors and provides resultant
vector

4.SIMULTANEOUS EQUATION SOLVER - Solves system of
simultaneous equations
FINANCE-PAGE (5255. j.svic sais Se $9.98 ....$7.95
1. CHECKBOOK BALANCER - Reconciles check register with
bank statement

2. NET PRESENT VALUES - Computes net present value of a
series of cash flows

3. AUTO LOAN ANALYSIS - Computes amount of loan and
monthly payments

HOMESPALS Lir eeeoc xexveo cnaxschpeqeeqtededa $29- ..$19.95
20 PROGRAMS - Best software value in America. All the pro-

grams in the above packages plus:
1. STAR INVADER - Mini space invader game with 1 invader
2. MACHINE LANGUAGE MONITOR - Utility program enters and
list hex code
3. RENUMBER - Utility program renumbers BASIC programs
4. 21 Page User's Manual (Manual alone $2.95 - credited to
future purchase of HOME-PAC)

COMMO oir hee uL $8.95 .... $6.95
Computerized variation of popular BOGGLE hidden word game
program, with 4x5 game board (2 to 8 players)

GUARANTEED
All programs are supplied on quality cassette tapes which are
guaranteed to load and run (defective software will be
replaced if returned within 3O days)

ACT NOW! CLIP and MAIL the COUPON BELOW!

Mail to: SIMPLEX SOFTWARE, DEPT. A4,

P.O. Box 792, New Brunswick, N.J. 08903

O Please send me more information. C Dealer information

Please rush my PRICE PRICE

order UNTIL 8/31 j|AFTER 8/31) QTY. TOTAL
PAC

MATHSTATPAG | 895 | 109s |

MANUAL

comso — | ee | aes | -

Shipping & Handling - (Foreign orders $3.00) 1.50
New Jersey Res. Add 696 Tax

Total

O Check O Money Order O VISA
O Mastercard

Account No. Exp.

Name

Address

City State Zip

FOR ZX-81 T/S1000 COMPUTERS

POLYMATH IS HERE TO HELP YOU!
Now you can transform your Timex/Sinclair computer into a
powerful teaching aid. Polymath will help you solve and check
your math problems, fast and efficiently.

Let Polymath be your computer tutor!
e Solve Quadratic Equations
e Solve Cubic Equations
e Fa.tor Numbers
e Find Prime Factors
e Find GCD's
e Evaluate Polynomials
e Evaluate for X and Y
e Plus much, much more!

16K RAM Reqd.

Solve equations quickly and accurately. Polymath is an entry
into the wider fields of science and technology. It will guide
you towards algebraic logic, the key to faster, efficient

programming. ORDER NOW

menu-driven Only $19.?5 ppd.

user-friendly POLYMATH
Written i
In a
Basic/MC vas
For

Of
Fast,
Crash-proof All Ages
Results.

Polymath comes on quality cassette with documentation.
To Order:

Send check or money order for $19.?5 ppd. To:
POLYMATH, P.O. Box 800, Felton, CA 95018
Calif. Res. Please add 6.5% tax
Orders Outside Continental U.S.A. add $1.°°

CRamiray *14°%°

| mummmmmmmm $
CLIIITTIIIE !

EEIE

Ac W 2040 Printer.

Our custom molded tray securely holds your
T/S 1000, T/S 16K RAM pak and cassette drive.
Control panel provides for optional switches. All
connecting cables are enclosed. For immediate
shipment send $14.95 plus $2.00 U.P.S. ($5.00
foreign) U.S. currency, check, money order,
credit card (type, number, expiration date).
Sorry, no C.O.D.

N9IS3Q
diNunsa WOUd

Free with every tray, Sinclair drivenPROM Burner sche-
matic, operating system software, and burn machine code.
You can burn and execute 2716, 2732, and 2732A. Copy
and duplicate software included. Boards, kits available.
For immediate shipment send ALL the money you have!
(or wait for our info pak)

Dealer and distributor inquiries invited.
RAM products made in U.S.A.
Ram 4736 N. Milwaukee Ave. - Chicago, IL 60630 U.S.A.

Robert J. Midura
19 Merrifield St., Apt 3F
Worchester, MA 01605

Mindware, Inc.
15 Tech Circle
Natick, MA 01760
(617) 655-3388
Note: Order all products
from:
Eagle Sales
15 Tech Circle
Natick, MA 01760

Robert C. Moler
5999 Secor Rd.
Traverse City, MI 49684

MT-Soft
Box 2638
Aurora, IL 60507

Mule Electronics
Dept. 310A

444 Lincoln BI.
Venice, CA 90291

New World Concepts, Dept. C

PO Box 587

Ogden, UT 84402
1-801-393-4819

Orbyte Software
PO Box
Waterbury, CT 06720
(203) 753-8308
Note: Prices include s&h: 3 or
more programs: 10 percent off.

Original Programs
3763 W. Crocus Dr.
Phoenix, AZ 85023

P.A.L.
PO Box 24362
Ft. Worth, TX 76112-9362

Panda Software
51 Elgin St.
Shelton
Stoke-on-Trent
U.K. ST4 2RD

Pegasus Micro Systems

PO Box 397

Chestertown, MD 21620
(301) 348-5865

People’s Computer Supply
PO Box 664
Sidney, NE 69162

Note: Products from: Memo-
tech, William Stuart Systems,
Advanced Interface Design,
Software Expense Cutter, USI
International Monitors, Bi-Pak,
Hunter, D. Fristch Electronic
Designs, Emvee Software, Key-
board George Risk Industries,
Haven Hardware, and others.

Plus + Pac Systems
International

PO Box 10300

Chicago, IL 60610
(312) 951-7671

Powerplay Systems
PO Box 752
New York, NY 11377

Praise Data Systems
205 Pawnee St.
Ronkonkoma, NY 11779

RAm
4736 N. Milwaukee Ave.
Chicago, IL 60630

Ramex International
PO Box 50
Utica, MI 48087

Rayco
PO Box 484
Delaware, OH 43015

Research Applications
Products

4561 Paloma Lane

Yorba Linda, CA 92686

John Riggs
1114 Elaine Ave.
Livermore, CA 94550

R-Tek
7326 Ridgeberry Dr.
Houston, TX 77095.

Run-it Software Club

732 S. Sherman

Chicago, IL 60605
(312) 427-6526

G. Russell - Electronics
RD 1, Box 539
Centre Hall, PA 16828

St. Martin's Press
175 5th Ave.
New York, NY 10010

Sight and Sound Electronics
1120 Bailey Hill Rd. #10
Eugene, OR 97402

(503) 485-6274

Sikes Software
PO Box 115
Edmeston, NY 13335

Silicon Valley North, Dept. SBG
PO Box 2442
Hammond, IN 46323

Sinclair Place
PO Box 2288
Redmond, WA 98052

Note: Products from: Thurnal
Electronics, Down East Com-
puters, Memotech, dk'Tronics,
Mindware, Aerco, Haven Hard-
ware, William Stuart Systems,
Kopak Creations, Abacus Elec-
tronics, Audiograph Co., Mel-
bourne House, Reston Publish-
ing.

Sinclair Supply Shack

22626 Woolsey Dr.
Novi, MI 48040

July/August 1983 © SYNC

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Sirius Ware
6 Turning Mill Rd.
Lexington, MA 02173

Skelly Computing
50 Riverside Dr. - Camelot
Lake Placid, NY 12946

SKT Enterprises
PO Box 23955
Washington, DC 20024

Softsync, Inc.

14 E. 34th St.

New York, NY 10016
(212) 685-2080

The Software Farm, Dept. C.

Craigo Farm, Botany Bay
Tintern, Gwent, U.K.

Software Supermarket
87 Howard's Lane
London, U.K. SW15 6NU

Sophia Systems
15122 Pheasant Dr.
Surrey, B.C.
Canada V3R 4X6

Sourceware, Inc.
PO Box 1579, Dept. SI-1
Vernal, UT 84078

Space Breaker
PO Box 8104
Green Bay, WI 54308

Spyder Electronics
PO Box 4172
Morgantown, WV 26505.

Stuart Software
25381-G Alicia Parkway,
Suite 316

Laguna Hills, CA 92653

Sussex Software House
57 Bexhill Rd.
Eastbourne

E. Sussex, U.K.

Syber, Inc.
1325 Diller Rd.
Ocean Springs, MS 39564

SyncWare Co.
PO Box 5177
EI Monte, CA 91734

Synergistic Design
PO Box 411023
Chicago, IL 60641

Tapemasters
PO Box 38651
Dallas, TX 75238
(800) 527-1227
(214) 349-0081 (in Texas)

Technology Products
and Services, Inc.
1012 Clearwater PI.
PO Box 10207
West Palm Beach, FL 33404-
1207

SPATS
BRESET?

No wobbles!
No bulky add-ons!

No fear of crashing if bumped!

The 64KT is 64k of user transparent memory
which mounts INSIDE the TS1000.

3G Company, Inc.

Rt. 3, Box 28a

Gaston, OR 97119
(503) 662-4492

Timeworks, Inc.
405 Lake Cook Rd., Bldg A
Deerfield, IL 60015

TS User (Yagsee Publishing)
PO Box 155
Vicksburg, MI 49097

Turner, Elcy & Com.
PO Box 395
Port Huron, MI

2-Bit Software

PO Box 2036

Del Mar, CA 92014
(619) 481-3629

UAS
Box 612
Haddonfield, NJ 08033

User Friendly Research
478 W. Hamilton Ave.,
Suite 154

Campbell, CA 95008

T. W. Vessels
Rt. 1, Box 77-S3
Brownsville, KY 42210

Sean Wilson
20 Lakevista Ave.

Bob Woish

102 North Lane, B3

Conshohocken, PA 19428
Note: All items sent postpaid.

J. M. Yocum
PO Box 1955
Corvallis, OR 97339

York 10 Computerware
24573 Kittridge St., Dept. S-4
Canoga Park, CA 91307

Youngs' Computer Publications
2 Woodland Way

Gosfield, Halstead

Essex, U.K. CO9 1TH

Zebra Systems, Inc.
78-06 Jamaica Ave.
Woodhaven, NY 11421

Zopf Industries
121 W. Mt. Hope
Lansing, MI 48910

Zor Khan
Box 31569
Aurora, CO 80041

Z-West

PO Box 2411

Vista, CA 92083
(619) 757-1387

ZXSystems Software
PO Box 8264

Markham, Ont. Canada L3P 1H5| Pembroke Pines, FL 33024 "a

SPYDER

presents the

ELECTRONICS

SPYDER CHARACTER BOARD

. Play and create high resolution games
. Create your own character sets

. Includes 2K of memory

. Use easy to read reverse video
. Compatible with RAM Packs and ZX Printer
. Installs easily (complete instructions included)

it installs in a minute with NO soldering .
Easy to follow instructions. To order the 64KT,
send $115.00 (pius $4.00 shipping & handling )
check or money order to:

INDEPENDENCE RESEARCH
P.O. BOX 1497
OREM, UTAH 84057

if you have a ZX81 , or a TS1000 with a serial + prefix
of T or D, specify the 64KZ

Included with the Spyder Character Board:

- Full documentation to get the most from your ZX81
- Demo tape with character sets

- Zap-Em high resolution game

- Spyder Software Catalog

Add $2.50 for
postage and handling

Bare Board -$14.50
Kit -$24.50
Assembled -$29.50

SPYDER ELECTRONICS
P.O. Box 4172
Morgantown, WV 26505

Send check or money order to:

USA funds only

July/August 1983 ° SYNC

iust For FLA

Horizontal Bar Graph
Michael W. Schultz

Type in the program. Then with your
computer in either FAST or SLOW mode,
hit RUN and ENTER. As the prompts
appear, enter the starting year of your
graph, the number of bars you wish to
compare, and the interval between years
(e.g.; 1, 5, 10). When the words
"HORIZONTAL BAR GRAPH" appear
on the screen, begin entering the data,
one number at a time. Each value must
be below 51 so scale your data accord-

Michael W. Schultz, 3650 Mossvale Dr. 20-D,
Mobile, AL 36608.

Generally SYNC prefers articles in some depth to help you get more out of your
computer. However, we receive many short programs that illustrate a point,
demonstrate a technique, or show something the reader has found interesting.
“Just for Fun" shares these programs with you. If you learn something, great. If
you have some fun, great. If you have some that you want to share, send them
to: Just for Fun, SYNC, 39 E. Hanover Ave., Morris Plains, NJ 07950.

ingly if you are INPUTting larger num-
bers. The first year entered will be shown

18 REM “HORIZONTAL BAR GRAPH“
20 PRINT “ENTER YEAR TO START

GRAPHY

RED'
6@ INPUT N

S0 PRINT “ENTER INTERVAL BETHE
=n YEARS

99 INPUT

iio SCR

DER PRINT TASB Si "HORIZONTAL BRE

— rm H“

8K ROM; 2K (1K) RAM

with its bar graph and the exact data
number. As each following year is shown,
the display will be SCROLLed up the
screen; after about twenty bars the display
will start disappearing off the top of the
screen.

This program is designed to be flexible
in structure so the user can easily edit it
to meet his individual needs, such as
personal finances, business applications,
and so on. This can be done by simply
changing the prompts in lines 20 and 80.

Bar graphs, either vertical or horizontal,
are very useful as visual aids in comparing
statistical values. Vertical graphs are more

Continued on page 114.

SINCLAIR
ZX81/TS1000

FORM FITTING

TIMEX 1000

BUSINESS

DUST COVER

Protect your ZX81 from dust, grime and spills with a
quality dust cover from The Computer Trader. The form
fitted cover provides protection during storage or
transport. Available colors: black, tan, royal blue,
brown, navy blue and burgundy.

DEALER & DISTRIBUTOR INQUIRIES WELCOME

Please include $1 postage and handling. Allow 1-3
weeks for delivery. Specify color and amount. *Califor-
nia residents add 6% sales tax.
The Computer Trader
P.0. Box 20976

San Diego, CA 92120

(619) 283-9273

July/August 1983 © SYNC

Budgeting

Inventory Control
Financial Analyzer
Stock Analyzer
Critical Path Analyzer
Bookkeeping

Leap Frog
Star Voyage
Fungaloids
Invaders
Chess
Snakebite
Packman

Assembler
Disassembler
Compiler

AND MANY MORE EXCITING PROGRAMS
CALL FOR FREE CATALOG
Shipping extra. No tax out of state.

DISCOUNT SOFTWARE, INC.

RCU PO BOX 2530, New York, NY 10185
Tel: (212) 486-0980

Se a TRE MM MINE
The 50 ready-
to-run programs
in this book will

show you how!
POLE ORE ED

If you suspect you're not getting all you can from
your Timex Sinclair 1000, here's a new book that will
make sure you do.

David H. Ahl has written 16 books about com-
puters. In The Timex Sinclair 1000 IdeaBook he puts
25 years of experience to work—to help you put
your computer to work.

The Timex Sinclair 1000 IdeaBook includes 50
complete, pre-tested programs— each one
designed to illustrate a specific problem-solving
technique.

By working these programs on your own com-
outer, you'll understand more fully its hidden
strengths. Plus, you'll learn how to overcome its
inherent weaknesses.

Armed with this knowledge, you're ready to put
your Timex to work performing a multitude of practi-
cal everyday tasks. Everything from balancing the
family budget, to taking inventory, to performing
science experiments.

Ten informative chapters show you how to solve
problems using:

e Repetitive trial e Geometry
e Convergence e Science

e Recursion e Simulation
e Compounding e Drill

e Probability e Practice

The Timex Sinclair 1000 IdeaBook is the only vol-
ume of its kind ever published for TS 1000 and ZX-81

y MAIL TODAY TO:
Order your copy today— | CREATIVE COMPUTING PRESS |
" , 39 n V
and start taking full ipe ca ee |

advantage of your TS 4000. į please send me

copies of the The Timex Sinclair 1000
IdeaBook for only $8.95 each, plus $2.00 shipping & handling per
book.

Total Amount $

O Payment Enclosed. (CA, NJ and NY, State residents please
add applicable sales tax.)

O Charge my: (Charge and phone orders: $10 minimum)
C] American Express O MasterCard O Visa

LOI dE 0S o E E VINO MRED AL ot oe Bs |) r TSW FL

Signature

NAM
(please print)
T um er 1 vu em io Bo |
PLOT IPALIT RERS fitt: RETURN iF MP ET PONE EE, CITY
ex Cnm 5 E 3 U UN CR
Ss [33
LOAD iv Ler 1
STATE DX pO Aun CR PCECUEE

"Outside U.S., add $3 for shipping and handling.

| O Check here to receive a FREE catalog of computing books,
magazines and guides.

For faster service, PHONE TOLL FREE:

800-631-8112
(In NJ only 201-540-0445)
Also available in your local bookstore and computer store.

:
|
|
:
|
!
|
Ww
ED Ll Seo pein SON tapis die NH EIL PII RR ea anne SES S SIT M Si T |
i
,
!
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|

Machine Code and Your TV Screen Harry Doakes

One of the ways that Basic is slow is in
putting things on the screen. Have you
ever played a game in Basic and you
wanted things to zip across the screen,
but, instead, they crawled? It is frus-
trating, but Basic is simply very slow in
this department. In the 8K Basic SLOW
mode, even something as simple as

10 FOR A=1 TO 10

20 PRINT A

30 NEXT A
takes a long time. (Try it and you will
see.)

You can speed up the process of put-
ting something on the screen by using
machine code, but, to do that, you must
have some understanding of how the com-
puter puts things on the TV. This is a
little technical, but do not panic— it will
not last long.

TV Guide

Somewhere in RAM there is a block of
memory called the display file. This is
where the computer stores what will go
on your TV screen. Depending on how
long your program is, the display file
could be almost anywhere in memory.
For example, when there is no program
in the computer, the display file starts at
location 16509 — near the bottom of RAM.
With a 16K RAM pack and a long pro-
gram, the display file might start way up
around memory location 32000— almost
at the top of memory.

To put something on the TV screen,
the computer has to know where the
display file starts. It keeps track of that
starting point as one of the "system vari-
ables." The people at Sinclair call this

Harry Doakes, PO Box 10860, Chicago, IL 60610

July/August 1983 © SYNC

particular system variable “D-FILE” (for
"display file"), and it is at the same place
for 4K and 8K Basic — memory locations
16396 and 16397.

Any time you want to know where the
display file begins, just look at those two
memory locations. In Basic, you can do it
like this:

PRINT PEEK (16396)+256*PEEK
(16397)

Notice that you must multiply what is in
the second memory location by 256, and
add it to what is in the first memory
location. This is similar to the way you
load a number into a register pair in
machine code—first comes the remain-
der, then comes the quotient.

Short and Sweet

One other thing you need to know
about the display file is that it is only as
long as it needs to be. The display file
takes up space that otherwise could be
used by a Basic program or by variables.
Since some Sinclair computers come with
only a small amount of RAM, it is import-
ant to use memory efficiently —and that
means keeping the display file short.

In the display file, each line of the TV
screen shows up as a string of character
codes (numbers between 0 and 63, or
between 128 and 191 for reversed char-
acters— white on a black background).
The last character code in each line is an
ENTER code, 118. (The complete list of
character codes is in the appendix to
your manual titled "The Character
Set.")

If a line on the TV screen is empty,
then the only thing in that line will be the
ENTER code. This is about as short as
you can get.

Taking a Look
Lets take a look at the display file.
Type in and run the program in Figure 1.

Figure 1.

10. PRINT HELLO"

20 PRINT
AQ PRINT
40 PRINT "OR"
wo) PRINT

60 FOR A=0 TO 12
ZOLEE C DE ELESRPEEK (162965)-425653

(16397)
B0 PRINT PEEK (DFILE+A)
90 NEXT A

Your screen should look like this:

The numbers in the bottom part of the
screen are the first 13 numbers in the
display file. If you check them against the
appendix of your manual, you will find
that they match up exactly to the first
dozen characters on the screen, including
the ENTER code at the end of each line.

But notice: the first byte in the display
file is always an ENTER code.

Quick-change Artist

When something is added to a line in
the display, everything in the display file
has to move—shifting down one position
to make room. That takes time, and it
can get pretty complicated. The easiest
way to get something on the screen is to
start out with something there, then
change it.

For example, try running the Basic pro-
gram in Figure 2.

Figure 2.

10 PRINT "X"
"20 LET DFILE=0

=O FOR A=0 TO 63

40 LET DFILE-FEEE (16296)-2564X
FEEK (16297)

BO PORE DFILE+1.4

40 NEXT à

(Line 20 is necessary only for running the
program in 4K Basic, in which the value
of "D-FILE" changes every time you
create a new variable.)

If your computer can run in SLOW
mode, you will see the character in the
upper left-hand corner of your screen
change quickly, running through the reg-
ular character set.

It runs pretty quickly, but, as you would
probably guess, it runs much, much faster
in machine code. How can we translate
this routine into machine code form?

The first thing we have to do is rewrite
the *FOR/NEXT" loop into a simpler
form. Remember, Z80 machine code has
nothing exactly like FOR and NEXT. The
results are shown in Figure 3.

Now we have solved the problem of the
loop; we can use load, increment, and
jump instructions to replace lines 20, 40,
and 50.

But we will also need to use two new
kinds of load instructions— instructions
that will work the way PEEK and POKE
work in Basic.

To do a machine code PEEK at lo-
cation 16396, use this instruction:

LD A,(16396)
The equivalent in Basic is

LET A=PEEK (16396)
However, you can use this instruction
only to load register A.

Remember, there is a big difference

between

LD A,5
and

LD A,(5)
The first one puts the number 5 in register
A. The second one puts whatever number
is in memory location 5 into register A.
This is the difference between

LET A=5
and

LET A=PEEK (5)

The number in parentheses is some-

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times called a pointer, and that is a good
way to remember how it works. It points
to where the computer will find the num-
ber it is going to load.

As you might expect, the machine code
version of POKE uses the same kind of
pointer notation. The instruction

LD (16396),A
works like

POKE 16396,A
The number in register A goes into mem-
ory location 16396.

Again, you can use this instruction only
to load register A.

Figure 3.
iO PRINT "X"

20 LET DFILE-O

3o LET Azo

40 LET DFILE=PEEK (16396)+256%
PEEK (16297)

SO FOKE DFILE-*1,4

60 LET &z6-1

70 IF A<64 THEN GOTO 30

Doing the T wo-step
You can also do a machine code PEEK

or POKE with the register pairs BC, DE,
and HL. One way is to load each register
individually. For example,

LD A,(16396)

LDL,A

LD A,(16397)

LD H,A

BACK ISSUES OF
Suri

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copies are still available. The more com-
plete your library of back issues, the more
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You may order any issues published
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July/August 1983 © SYNC

would load the system variable “D-FILE”
into register pair HL.
But you can do the same thing with a

single instruction:

LD HL,(16396)
This automatically loads the number at
location 16396 into register L, and loads
the number at location 16397 into register
H. It does two steps at once. This is faster
for the Z80 processor, and easier for you.

You can also use this instruction with

the other two register pairs, BC and DE.
And you have probably guessed already
that, if you can PEEK with any register
pair, you can simply reverse the process
to do the machine code equivalent of a
POKE. You are right—

LD (16396),HL
is equivalent in Basic to

POKE 16396,L

POKE 16397,H

Pointers by the Pair

So far, we have covered the ways that
you can PEEK or POKE to a specific
numbered location. The number in par-
entheses in the machine code instruction
always points to the memory location that
is involved.

But in Basic, you can also use PEEK
and POKE with variables, e.g., commands
such as

LET A=PEEK (HL)
or

POKE HL,A
Can you put parentheses around the name
of a register in machine code, and use it
as a pointer?

Yes, but only sometimes.

A memory location is a number be-
tween 0 and 65535. That means it will
take two registers—a register pair—to
handle the number. As a result, you can-
not say

LD A,(B)
but you can say
LD A,(BC)

In addition, register pairs BC and DE
can be used only to PEEK or POKE with
register A. Remember, register A is
special. It is the register you can add to or
subtract from, and it has many of its own
special instructions we have not seen yet.

Here are the only machine code PEEK
and POKE instructions that use register
pairs BC and DE:

LD A,(BC)
LD A,(DE)
LD (BC),A
LD (DE),A

That is not much, certainly. What about
register pair HL?

Pay close attention here—this is
important:

In almost any instruction in which you
can use one of the seven regular regis-
ters—A, B, C, D, E, H, and L—you can
also use register pair HL as a pointer.

July/August 1983 © SYNC

Here are a few examples:
LD B,(HL)
LD (HL),E
ADD A, (HL)
CP (HL)

If you stop to think about it, you will
realize that is pretty impressive. This
means you can use almost any memory
location just like a register, so long as
register pair HL is pointing to that mem-
ory location.

Whew

By now you are probably ready for a
rest. But we are so close to being done
with the machine code version of our
quick-changing number program, so let’s
finish it up fast. Figure 4 shows the pro-
gram so far.

Figure 4.
10, PRINT "X^
S0 LET DFILE=0
AO LET A=
40 LET DFILE-FEEK £16296)-r226X
PEEK (162397)

20 FORE DFILE-1.64
60 LET A=At+1
70 IF 6264 THEN GOTO 3o

If we use register A for A and register
pair HL for DFILE, we can translate it
just about line by line. Starting with line
30, Figure 5 shows what we have so far.

Figure 5.
LD 6,0 62,0,
LD HL. £16296) 42,12,64,
INC HL. arbe
EGO C oD i75
INC A 40,
CF 64 2584,64,
Gu -5 es bi
RET 201
Figure 6.

ido LET (13217390

20 FOR A=O TO 12

A0 PRINT A; "SHHBHEHSHH" ;
40 INFUT E

20 POKE e*G.HR

60 PRINT FEER (AtQ),
70 NEXT A

930. CLS

qu PRINT AS

190 LET H=USR (09)

Figure 7.

20 LET DE-FEEK (16396)+256*PEE

Ko £(16597)

30 LET DE=DE+20
40 LET HL=DE

SO LET A=FEER
60 LET A=Â+1

70 IF A<38 THEN GOTO 110
80 FORE HL., 28

90 LET HL=HL-1

100 GOTO 50

110 FOKE HL.A

120 GOTQ 3o

CHL)

Now let’s poke this routine in and run it
using the loader program in Figure 6.
(Notice that PRINT “X” is part of the
Basic program.)

First reserve space at the top of mem-
ory like this:

4K ROM: Type

PRINT USR(620)
Wait until the screen clears. Then type
again
PRINT USR(620)
8K ROM: Enter this program:
10 POKE 16388,-20
20 POKE 16389,PEEK 16389-1
30 NEW

The program in Figure 6 is designed
for a ZX80 or ZX81 with 1K of RAM.
For a 2K TS1000, change line 10 to

10 LET Q— 18414
If you are using a 16K RAM pack, change
line 10 to

10 LET Q=32750

Now, for either ROM, type in the pro-
gram in Figure 6.

Run the program and enter the num-
bers in the right-hand column of Figure 5
in exactly the order they appear.

Now you will see the character change
even faster than the TV changes the
screen —you may find it hard to believe
anything happened at all. That is fast.

Doing It Yourself

You can also use the PEEK function to
find out what is in a particular location
on the screen. Figure 7 gives a short
program that turns your display into a
counter.

Can you work out the machine code
program that will do the same thing? If
you try running it, watch out— the lowest
digits will probably flash by so fast, you
will not be able to see them at all.

Variables —in Machine Code?

Now we know how to move a number
between a memory location and a regis-
ter. We can move the number from a
register to a memory location (like the
POKE command in Basic), or move it
from the memory location to a register
(like the PEEK function in Basic).

Besides looking at and putting things
on the TV screen, there is something else
we can use the machine code PEEK and
POKE for—something even more useful
and important. With these instructions,
we can create our own machine code
program variables—as many of them as
we like.

. Here is how it works:

Suppose we designate a specific byte
of memory as a variable. (The best way is
to choose a byte of memory that is near
the machine code program. That way, it
will be in protected memory, and will not
be accidentally changed by the Basic sys-
tem.) We can store a number at that

With variables, it is easier than ever to translate a program
from Basic to machine code.

memory location, and put the number
into a register only when we need it.

For example, if we have a variable at
location 17000, we can add 5 to it with
these instructions:

LD A,(17000)
ADD A,5
LD (17000),A

A one-byte variable can hold any num-
ber from 0 to 255. To hold a larger num-
ber, we can use a variable that takes up
two bytes. It can hold any number from 0
to 65535. We could add 5 to that kind of
variable like this:

LD HL,(17000)
LD DE,5

ADD HL,DE
LD (17000),HL

Think for a moment about what this
means. Up till now, we have only had a
few registers to work with. Asa result, we
could keep track of only a few numbers
at once—one number in each register.
But by using variables in our machine
code programs, we can keep track of
many different numbers. There is really
no limit to the number of variables we
can use in a machine code program

*
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except the amount of available memory.

However, we must keep in mind that
using variables takes more instructions
than keeping all the numbers in registers.
It also makes your machine code pro-
grams run a bit slower since it takes time
to get variables from memory and load
them into registers, and then to move
them back from registers into memory
after you are finished working with them.

It takes time—but not much time. For
example, on your computer it takes an
extra 8 one-millionths of a second to get a
one-byte variable and then put it back.

That kind of time, we can usually
afford.

Figure 8.
LO A, (17002) get R
LD BLA
LD 5,117003) get S$
ADD ÂA, B add them

LD (17001)5,68 put result in Q

There is a big advantage to using
variables, though, that really makes it
worthwhile. With variables, it is easier
than ever to translate a program from
Basic to machine code. A few more in-

FOR
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structions are required than before, but
with variables you can translate lines of
Basic more directly.
Up until now, for example, we have
had trouble with a line like
LET Q=R+S
First we had to break it down to
LET Q=R
LET Q=Q+S
and then decide what registers to put the
numbers Q, R, and S in.

But with variables we can translate the
single line of Basic into a series of ma-
chine code instructions. If Q is the vari-
able at memory location 17001, R is at
17002, and S is at 17003, then

LET Q=R+S
becomes as in Figure 8.

Get the idea? It may seem a little more
complicated, but here is the key: you can
always use exactly the same routine to
add two variables together and put the
result in a third variable. To do the same
thing with three different variables, all
you have to do is plug different variable
locations into this same set of instruc-
tions.

Remember that machine code has no

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error messages, and a mistake will prob-
ably make your computer crash. Then
you have to unplug the computer and
start all over again from scratch. Keeping
track of what you are doing on paper or
tape may save redoing a lot of work.

The more you can use "standard"
chunks of program —like this routine for
adding two variables together, the easier
it is to write machine code routines that
will not crash.

What is more, in Basic, you do have
error messages, and, if there is a mistake
in your program, it usually means you
have to change just a line to fix the
problem, then run it again. One easy way
to write a machine code program is to
start out by writing the program in Basic,
making sure it runs properly, then trans-
lating the program into machine code, to
get all the advantages of machine code
speed.

It may not quite be all the best of both
worlds, but it comes a little closer.

Coming Attractions

There is another big advantage to using
variables in our machine code programs:
it makes it easy to send a number into a
machine code routine.

We already know how to get an answer
out of a machine code program. When
the machine code routine hits the "return"
instruction, the value in one of the register
pairs will be returned to Basic. This is the
HL pair on the 4K ROM, or the BC pair on
the 8K ROM.

But suppose we have a machine code
routine that can draw a line on the screen
from one point to another. How can we
tell the routine what two points to draw
the line between?

If we have made the coordinates of the
two points variables in our machine code
routine, it is easy. Since we know the
memory locations of the variables, we
can POKE our coordinates into the vari-
ables from our Basic program, before it
reaches the line where the USR function
sets the computer to work on the machine
language routine.

We can also get as many answers as we
like from a machine code routine, by
PEEKing at the variable locations after
the computer has returned to Basic. Usu-
ally we will not need to do that, but it is
nice to know we can.

Next time, we will look at a machine
code line-drawing routine that is not only
much faster than Basic, but much smaller,
too. The Basic version barely fits in a
computer with 2K RAM, while the ma-
chine code takes up less than 300 bytes.

If you have comments or questions
about machine code programming, or if
something is not quite clear, let me hear
from you. Be sure to send along a stamp-
ed, self-addressed envelope if you need a

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Adding a Counter in Hardware Bernard Puerzer

Sure, we all know computers are smart,
but can they tell time? Not without some
work.

Since getting my computer, I have been

Bernard Puerzer, 3209 S. Kinnickinnic Ave.,
Milwaukee, WI 53207.

OSCILLATOR

* 5 VOUS

7 0.01uf

10
Ges DD,

LOW COUNT EN

HIGH COUNT EN

A15 (8k ROM)
Al2 (4K ROM) 1

MREQ

Al4

ENCODER

COUNT CLR

interested in configuring it to send and
receive Morse code and display it on the
screen. The first problem, discussed in
my article “Machine Code Keyboard
Scanning” (SYNC 1:4), was to figure out
how to read the MicroAce/Sinclair key-
board. This is needed for the transmit

Figure 1. Counter Circuit Schematic.

COUNTERS

*+ 5 VOUS

COUNT CIR
+ 5vOUS

LOW COUNT EN

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COUNT CLR

Parts List.

PART # RADIO SHACK
Ul- 74LS14

U2= 74LS08 276-1822

U3= 74LS138 276-1939

U4= 556 TIMER 276-1728
U5-7= 74LS161

U8-9= 747185244 276-1941

THE 74LS14 and 74LS161 are available
at most electronics parts stores.

LOW COUNT EN

e
COUNT CLR
+ $VOUS
IK
14

portion of this task. Next I added 16K
RAM to hold the program and Morse
Code message buffers.

I was now ready to take up the next
problem: I needed to know how long the
Morse Code key is held down to deter-
mine if it is a dot or a dash. I also needed

D3 SINCLAIR/

Ba MICROACE
EDGE

D5 CONNECTOR

| ie
HIGH COUNT EN

July/August 1983 ° SYNC

to know how long the Code Key is up to
determine if the last character received is
the last character of the word or not. If it
is, I need to display a space before the
next word.

So I needed a timer to tell the time
between one event and the next. I did not
want to add hardware if the same job
could be done through programming be-
cause my list of test equipment includes
an analog voltmeter and that is it.
Troubleshooting a program seems some-
what easier to me than troubleshooting
microprocessor hardware.

But, in this case, there is no way around
adding hardware if I wanted an accurate
counter. The MicroAce/Sinclair has a
memory location that is incremented 60
times per second if a display is on the
screen, but I could not be sure there
would always be a display. Besides, it
increments every 16.7 Msec, which is too
slow for my application. So I needed a
timer in hardware. Such a timer that can
run while the computer is doing some-
thing else can be a benefit in many other
applications as well.

Design

There are several ways to add a hard-
ware timer to the MicroAce/Sinclair.

My first attempt was to use a Z80
Counter Timer Chip (CTC). This really
quite marvelous device allows the user to
program any of 4 channels to be either a
counter or a timer, with an interrupt
generated when the counter reaches zero.
I spent many frustrating evenings design-
ing and constructing a circuit using the
CTC chip but to no avail. I just could not
get the MicroAce to program the chip.
At this point I was convinced that the
CTC chip that I had was bad.

So I had to decide whether I wanted to
purchase another one ($6-15 depending
on where you order it and how long you
want to wait for it) or to come up with
another design. The challenge of a new,
simpler design (also a flat wallet) won
out.

So I proceeded to develop a design
using 74LS161 counters (cheap and easy
to acquire). First I had to determine the
smallest and largest time intervals needed.
For my application I needed intervals
between 0.1 Msec and 100 Msec. This
would allow me to transmit and receive
Morse Code at about 3 to 30 words per
minute.

Then I designed an oscillator that
would put out pulses of 50 usec (one-half
the smallest time that I need). This oscil-
lator would feed a counter comprised of
three 74LS161 counters which give me 12
bits output (4 bits per counter). This
allows the counter to count from 0 to
4095. Since I am counting 50 usec inter-
vals I have the ability to count from 504
sec to 204.8 Msec (4096 x 50 u sec). This

à a é
X WEE

M >
A 4 & é
: n mm — cnm Rs to

Figure 7. Buffer board (see Figure 4).

Figure 8. Prototype board (16K RAM and counters) connected to buffer board.

Figure 9. Prototype board in place.

CONVERSION

FOR
YOUR
Z2X-81/ V. T dh
TS-1000 DUTY

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1-800-421-5775

(Order Desk Only)

* 6.6” wide, 3.2"
high, 1.08" deep

is twice the time I need to measure, and
so more than adequate for the job. More
of these counters can easily be added to
obtain any number of counts needed.

The oscillator uses a 556 Timer chip
that I had in my parts box. This chip is a
dual 555 timer, but I am using only one of
the timers. The 555 or 556 chip is readily
available. A 555 chip can be used, but be
careful because the pin-out is different
from the 556 pin-out shown in the sche-
matic (Figure 1). Since I am using this
chip as a free-running oscillator, I chose
the values of RA, RB, and C to cause an
oscillation of 20 Khz (50 usec).

If you want your counter to count at a
different time interval, use the following
formula to determine the RA, RB, and C

values: oup
pe.

F(Frequency) — 1 (time interval) —
XE UT

(RA + 2RB) x C

When choosing RA and RB, you must
also be aware of the duty cycle— the ratio
of the time the waveform is low (or high)
to the time it is high (or low). The fol-
lowing formula determines the duty
cycle:
RB
Ij)
RA + 2RB

The CRASH GUARD is made of Heavy Gauge Bronze-
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Figure 2. Duty Cycle of 25%.

uc Wem COD LU

~zn —
High 75% Low 25%
Figure 3.
Operation Address Generates Active Comments
4K ROM 8K ROM low signal

READ or WRITE 4096 32768 Count reset Resets all the
counters to zero.

READ only 4097 32769 Low Count EN Reads the low order
8 bits of counter.

READ only 4098 32770 High Count EN Reads the high order

For example, the calculations for a count-
er that counts time invervals of 50 u sec
(as I need) are as follows:
1) Choose 0.01 uf for the C value:
20 x 10° Hz =
1.44
(RA + 2RB) (0.01 x 109 ) farads

RA + 2RB =7.2x 10° — 72K ohms
2) Choose 2 resistor values such that
RA + 2RB = 7.2K
I chose RA = 3.6K and RB = 1.8K
3.6K + 2(1.8K) = 7.2K

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4 bits of counter.

3) The duty cycle is:
LER >
ORAS US

This means that the waveform is low for
25% of the time. It will appear similar to
Figure 2.

Although not critical, for this appli-
cation try to keep the duty cycle between
about 10% and 90%.

The oscillator will feed the string of
74LS161 counters which will count up to
the maximum count (in this case 4095)

"CRASH GUARD"

PROTECTS YOUR ZX81
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* Helps prevent accidental unplugging of
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Figure 5. Low order counter test.

; Address Decimal Instruction Comments t States
then go back to zero and automati |
Bae 8 | automatically ,,,.5 33 32 78 LD HL,20000 START OF DISPLAY BLOCK
egin counting up again. Since the 15:33 50 0 ié LD (4096),A CLEAR COUNTERS
output of the counters is always active, en ee ed : ED EUNT Dro E E E
| : i&438 58 i5 ACK LD A, (4097) LOAD LOW COUNTER VALUE = t-13
I must place their outputs on the data — i21:; iis LD (HL),A LOAD DISPLAY BLOCK £27
line only when I want to read them. 16442 è 9 LD B,9 DELAY OF 117 t STATES t=7
Therefore, I needed the 74LS244 buffers 16754 te 295 a ho vo nti ag
that are enabled onto the data bus only iés 35 INC HL t=4
when their pins 1 and 19 go low. Since 15277. 12. 2, 1, ra te nce de
e . 2 1 hii] at ; vi- , CH t=
there are only 8 data lines, obviously all 14451 20: RET
12 bits cannot be read at once. So I
needed to control the counter string in bits on the data bus, and a High Count — |. s icit: M MI as a
. d vis Fw . . 5 ( caaracvers t
groups of 8 bits. In my design a Low EN places the remaining 4 high order bits hüid mahhine EUR
Count EN signal places the low order 8 on the data bus. Therefore to get the 20 LET K=USR (16430)
30 FÜR I=20000 TO 20200
40 PRINT PEEK(IJ,
50 NEXT I
60 STOF

Extend your ZX81/TS1000:
Add Memory that wont Forget!

^ ADD YOUR OWN SYSTEM UTILITIES

^ BUILD UP A LIBRARY OF MACHINE
LANGUAGE SUBROUTINES

^ UP TO 8K NONVOLATILE RAM
^ USE HM6116LP CMOS RAM S AI M
OR 2716/2732 EPROM o ES

»^ COMPATIBLE WITH
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plus $1.95 shipping and handling

d i

i)» READ THE REVIEWS:

What a super product! ...conceived and executed very nicely...and with quality components.
(SYNTAX QUARTERLY Winter 82)

8K Nonvolatile memory is a gem! It has so many possible uses...| recommend this board most heartily.
(OKLAHOMA S.U.G. Newsletter 1/3)

We found the documentation to be far superior to that (of) most hardware we've received.
(S.U.N. Newsletter Nov/Dec 82)

For versatility this is even better than an EPROM...ranks quite high on the list of “must-haves”...
, (SYNC Magazine Mar/Apr 83)

INTRODUCTION

This memory board is designed to fill the transparent 8K
block of memory (from 8 to 16K) in a ZX81-16K system.
This area of memory is an ideal place to store, either per-
manently or temporarily, machine language routines or
data which are to be used by the BASIC system.

A sample display routine, a program— merging routine,
and procedures for storing utilities on tape are included
with the kit.

The use of HM6116LP 2K CMOS RAM memory IC's with
their own reserve power supply means that routines stored
in the RAM are nonvolatile — the RAM retains its memory
even when the ZX81 is switched off or reset. Moreover, be-
ing RAM, the routines you store in the memory are easily
modified. The lithium cell supplied with the, board will main-
tain sufficient reserve power for almost ten years.

ASSEMBLY

Complete step-by-step instructions in a 20 page manual
make assembly of the board easy. Construction takes be-
tween two and three hours. The kit (pictured above) is
complete with a silkscreened solder-masked printed cir-
cuit board, all capacitors, resistors, transistors, sockets,
connectors, integrated circuits, and the lithium cell. The
board is supplied with one 2K CMOS 6116LP-3 RAM — it
will accomodate three more for a total of 8K.

Complete kit with 2K $29.95
Additional three 6116LP-3 $16.00
Bare pc board & manual $13.05
Assembled & tested with 2K $44.95
Assembled & tested with 8K $59.95
Shipping & handling per order $ 1.95

Send check or money order to the address below.

HUNTER, 1630 FOREST HILLS DRIVE, OKEMOS, MI 48864

total count value, two read instructions
are necessary. (See the application section
below.)

Decoding

Three memory addresses that contain
nothing (no ROM or RAM) are needed to
map the counters into. On the MicroAce
with the 4K ROM, the memory from 4096-
8193 is not used. With the 8K ROM and
up to 16K RAM, the memory area above
32767 can be used. This is shown in Figure
1. Just substitute A15 for A12 in this
article for use on the computers with the
8K ROM.

I wired up the 74LS138 decoder to be
enabled when both the MREQ signal and
the address line A12 are asserted. Note
that the LS138 is disabled if A14 is asser-
ted since this would be an address in the
16K RAM area (located at addresses
16384-32767).

Wiring pins 1, 2, and 3 of the LS138 to
address lines AO, A1, and A2 gives active
low signals when the addresses shown in
Figure 3 are asserted. The LS138 decoder
(address 4099-4111) has five more outputs
that can be used for future expansion.

Since the counters free-count asyn-
chronous to the MicroAce, we might get
an inaccurate count (some bits might be
at the transition between high and low) if
we read the counter when the count is
changing. Therefore I gated the Low
Count EN and High Count EN signals
with the oscillator output (LS08) to disable
any counting while the counter is being
read. No counts are lost because it only
takes 4 {£seconds to read the counter. I
also used the 74LS14 Schmitt trigger in-
verter to give me a sharp edge from the
556 oscillator. This was probably not
needed, but, since it worked, I kept it in
the circuit.

Construction

One of the major problems in adding
hardware to your computer is where to
put it. I had a wire-wrap prototype board
to put the counter ICs on, but interfacing
it to the MicroAce was a challenge. I had,

July/August 1983 ° SYNC

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as I am sure. most of you have had, a
difficult time finding a suitable edge con-
nector for the MicroAce. Also I wanted
to buffer the signals on the edge con-
nector as close to the connector as I could
to increase signal drive and reduce noise
pick-up. |

Therefore I built the small buffer board
with 74LS244 buffers on it, wired as shown
in Figure 4. This small buffer board was
mounted with a spacer above the Micro-
Ace edge connector (I drilled a small
hole in the corner of the MicroAce circuit
board, being careful not to drill through
any circuit runs). Then I carefully solder-
ed the connections from the buffer board
to the MicroAce edge connector using
short lengths of wire-wrap wire. The buf-
fer outputs were soldered to a 37 pin D
connector also mounted on the buffer
board. Since D connectors are readily
available, I felt this was a good choice.

So now all the edge connector signals
are buffered except the 8 data lines. These
are difficult to buffer because they are 2-
way signals. The buffer must be steered
to or from the Z80 CPU depending on
whether a read or a write is being done.
Since I was not sure what circuitry to put
on the prototype board, I decided to
buffer the data lines on the prototype
board and not the small buffer. board.
Therefore I ran the data lines directly
from the edge connector to the D con-
nector. As it turned out, this counter
circuit alone will work fine without any
buffering, but, since I also added 16K
RAM to my prototype board, I felt the
buffering was needed. I then connected
my prototype board edge connector to a
mating D connector with about 10 inches
of wire. This makes removal of the proto-
type board from any system quite easy.

Testing

So now the counter is wired up and
power is applied. The prompt comes up
on the screen, so I know at least the
MicroAce still works (that is reassuring
anyway). But how do I test the counter?

I wrote two short programs (Figures 5
and 6) that are a combination of machine
code and Basic. Load in the machine code
starting in location 16430 (location 16520
in 8K ROM systems). The first Basic
statement should be a REM statement,
long enough to hold the code then scrol-
led off the screen with PRINT
statements.

The program in Figure 5 tests the low
order 8 bits of the counter. The program
resets the counter then reads the counter
every 50.4 u sec, displaying the result.
The display should go from 0 to 255 but
will skip a number every so often since
the counter counts at exactly 50 u sec but
the program reads the counter every 50.4
M sec. This was good enough for a
functional test. I did not want to fine tune

Figure 6. High order counter test.

Address Decimal Instruction Comments t States
16420: 31. da VB LD HL, 20000 START OF DISPLAY BLOCK
1545$. 4.99. ^ 06. "T6 LD (40963,4 CLEAR COUNTERS
16436 14.355 LD 6.255 DISPLAY COUNTER
1543B 199 (3 BACK Gees thee Re. DELAY LOOP t=7
tés05 58. 2-16 LD A, (4098) LOAD HIGH COUNTER VALUE t-i3
16443 230 15 AND OOO001111B MASK OUT UPPER 4 BITS t-4
16448 ii9 LD (HL),A LOAD DISPLAY BLOCK t=7
YEAdEX*els" CRAs AGAIN1 LD Bb, 244 t=7
1544E ib 254 AGAIN — DJNZ AGAIN DELAY OF 41548 t STATES t=1i3
16455 21 ue p (12.78 Msec) t=7
16451 194 62 64 JP NZ AGAINI t-10
15454 35 INC HL t-6
14455. 13 DEO. c t-4
ijg. 1194 54 54 JP NZ; BACK £-10
ié459 20i RET Basic program

10 REM (PUT IN 40 Characters to

hold Machine Code

the program to read the counter every D0 2s LET KEUSR(16420)
usec. The time a program takes can be zc FOR I-20000 TO 20254
calculated by counting the number of t B MEAN
states each machine code instruction bG STOP

takes. On the MicroAce/Sinclair, 1 t state
= 308 usec.

The program in Figure 6 checks the
high order 4 bits of the counter. It resets
and reads the counter every 12.808 Msec,
displaying the result 200 times. The dis-
play should go from 0 to 15 and increment
every 12.8 Msec. If the low order counter
works but the high order counter does
not, check the ENT and ENP connections
(pins 7 and 10) on the high order counter.

Application

To use this counter most effectively, it
is best to reset the counter at the begin-
ning of the time interval to be measured,
then read the counter at the end of the
time interval. This will give you the num-
ber of 50 u sec intervals that have expired.
Remember that, when the counter reach-
es its limit (4095), it goes back to zero and
starts counting again. Therefore the time
interval that you measure cannot be larger
than 4096 x 50 u sec = 204.8 Msec. If it is,
either change the 556 oscillator resistor
values to obtain a slower frequency or
add more 74LS161 counters to your
circuit.

The two most convenient ways to read
the counter are:

1) In machine code, load one of the
register pairs, for example, HL, as follows
for 4K ROM:

LD A,(4098) ;read high order count

LD H,A

LD A,(4097) ;read low order count

LD L,A

Now register pair HL contains the full 12-
bit count.

2) In Basic, read in the high order
count, multiply it by 256, then add it to
the low order count. For example, for the
4K ROM:

LET A=PEEK (4098)
LET B—A*256

LET C=PEEK (4097)
LET C=PEEK (4097)
LET D=B+C

For the 8K ROM, change 4097 to 32769,

Figure 4. Interface board.

TO SINCLAIR/MICROACE EDGE CONNECTOR
TO PROTOTYPE BOARD

WR
MREQ MREQ
RD RD

74LS244

and 4098 to 32770. above. The number in
variable D is the full 12-bit count.

We hope that you will be able to use
this hardware timer for your purposes— It
can be used for anything from designing
an alarm system to displaying the correct
time while your program is running. Good
luck in your timing applications. Now you
can tell your doubting friends that com-
puters are really smart; just look, they
can count and, with a little programming,
they can even tell the time!

Buyer's Guide Supplement

7 pric f rey. copy ona fist come, pue serve basis,

Improving Your

Computer

Computer Practice Keyboard Co.
Portable Keyboard
$4.95 pp.; 2 for $8.50.

Learn and practice your keyboard while away
from your computer. Regular typewriter key
positions and special functions. Printed on
sturdy 8 1/2 x 11 stock to fit standard binders
with plastic lamination. Available for Timex,
Apple, Atari, TRS-80, TI 99/4, IBM, Com-
modore, Wang, Xerox, Osborne, and others.
Specify which computer keyboard you want.

Datametrics
ZX81 Dust/Dirt Cover. £3 plus s&h.

Covers available in black, red, brown, green;
made in durable padded P.V .C. with facility for
storing leads; keeps your ZX81 clean and free
of dirt.

Daydesign
My Type
16K RAM. Cassette: $8.

Teaches touch typing on your ZX81 key-
board. Features include key location, review,
token command drills. Mistakes and WPM given
at end of each lesson.

Big-Key Legends. $7 per set.

Dry transfer keycap graphics in red and black;
identical to those on the ZX/TS keyboard. For
use on full size keyboards with standard 1/2"
key caps.

Dynamic Designs
Control Module. $27.50 plus $2 s&h.

A powerline switch, power "ON" indicator,
LOAD/SAVE isolation switch with LOAD level
monitor and Reset control. Isolation switch
prevents feedback during program SAVE. Reset
allows recovery from crashes without powering
down peripherals. 2 3/4" x 2 x 1 1/4". Can be
mounted on top of computer or used alongside.

Reset Control. Kit: $4.50 pp.

Add system Reset capability to permit quick
recovery from crashes without powering down
peripheral equipment. Control attaches to com-
puter with two wires. Complete instructions for
mounting and use.

100

N. J. Gipson
Self-Starting Program Unlocker
Cassette: $13.95 pp.

No more worries about program tapes you
cannot back up; no more programs you cannot
LIST and modify. Changes any tape program to
allow Basic commands immediately after
LOADing. Lifetime Guarantee.

Laserscan Electronics Corporation
16K extender RAM Pack.

Kit: $39.95; assembled: $44.95.

PC Board with connectors: $24.95.

Highly crash resistant RAM pack that can be
mounted inside the computer under the key-
board or plugged directly into the rear con-
nector. Requires no extra power supply; comes
with a special high pressure edge connector
employing gold plated, bifurcated contacts that
will not allow the system to crash due to vi-
brations. Allows the use of the printer.

R-Tek
Copy-Cass. $19.95 plus $2 s&h.

Software backup system interfaces two in-
expensive cassette recorders to provide a reli-
able method of tape to tape transfer of any
program compatible with ZX80, ZX81, and
TS1000 computers. SASE for free brochure.

G. Russell - Electronics
Key Load
16K RAM. Cassette: $10.

Unlocks those unSAVEable, unLISTable cas-
sette programs. After LOADing this short ma-
chine language program, any TS/ZX cassette
program subsequently LOADed instantly be-
comes SAVEable and LISTable. Now you can
make a clean, easy to LOAD, back-up copy of
that valuable cassette program.

Extending Your

Computer

Ener-Z
Report Generator
$69.95 plus $3 s&h.
Data acquisition and control board: Cen-
tronics printer interface supports LLIST,

LPRINT, COPY ; real time clock with battery
backup; 8 bit I/O ports; CMOS A/D converter.
Features: Bus connector for RAM pack; ROM
resident firmware; I/O mapped.

Intercomputer Inc.

Flexible Ribbon Connector (PL7016). $17.95.
A flexible ribbon for connecting any Memory

Expansion, Softbox cartridges, and Intercon-

troller to your TS1000. Prevents the usual system

crashes caused by RAM pack movement.

Intercontroller (PL7013). $34.95.

Put your TS1000 to work around the clock.

and do any number of tasks automatically (e.g.,
turns on/off your lights, motors, waters your
lawn). Just plug Intercontroller into your com-
puter and program each of the three switches
individually. Software programmable with time
intervals from fractions of seconds to days.
Connect up to four Intercontroller units to your
computer with a Softbox.

Kabre Electronics

Automatic Repeat Function. $15.95 pp.
Module with built-in self-test LED, automatic

and continuous character input. Saves time and

editing.

MAV Microproducts
EPROM Programmer/Reader
$64.96 plus $3 s&h.

Uses two 4K 2732 EPROMsSs in the 8-16K slot.
Housed in slim plastic lie flat case with ribbon
connector and expansion port making it com-
patible with RAM packs, printers, etc. Uses
zero insertion force sockets for programs that
failsafe load in seconds instead of minutes.
Assembled and tested, with one EPROM. Extra
EPROMs: $4.95 each.

Spyder Electronics

The Spyder Character Board

Kit: $24.50; assembled: $29.50; bare board:
$14.50; $2.50 s&h.

A 4K (2K populated) memory expansion that
allows changing of the ZX81/TS1000 character
set; in the transparent region between 12 and
16K ; may be populated with 6116 RAM or 2716
EPROM sS. Spyder offers EPROM programming.
Full documentation and two programs on cas-
sette are included.

July/August 1983 ? SYNC

Timeworks, Inc.
Computer Control Center. $29.95.

On/off switch eliminates constant plugging
and unplugging. Accommodates all brands and
sizes of RAM packs and a 13” screen monitor;
angled for maximum display and viewing. Pock-
ets for tapes; openings for TS Printer and cas-
sette deck hookups. High impact, molded poly-
styrene case gives a sleek, sophisticated, profes-
sional look. Cords and wires hidden under the
unit. 3 5/8" x 20" x 14 1/2”.

Programming Your
Computer

A + Associates
Understanding Sinclair Basic
16K RAM. Cassette: $10 plus $1 s&h.

Fully demonstrates all of the Sinclair Basic
commands and statements. You control the
speed of the demonstration. Repeat each pro-
gram as you need. If you are having difficulty
with the manual, this program will simplify your
problems.

TS/Basic. $3 plus $1 s&h.

A Basic programming form. High quality
erasable bond paper 8 1/2 x 11. 24 line screen
mapped on the front; 22 line screen on the back
with coordinates; varied line density for legi-
bility; area for notes and variables.

Biocal Software

(See Directory of Suppliers for prices.)
Base-N

Convert numbers from one base to another
quickly; up to base 36. Includes decimal frac-
tions.

Menu
Tape loader program, menu driven. Add,
change, delete, sort, list.

Note-pad
Full screen editor; supports cursor movement
up, down, left, and right. Multipage storage.

Daydesign
My Type
16K RAM. Cassette: $8.

Teaches touch typing on your ZX81 key-
board. Features include key location, review,
token command drills. Mistakes and WPM given
at end of each lesson.

Intercomputer Inc.
Assembler/Debugger ZXAD (PT 4003)
16K RAM. $18.95.

Write machine code quickly and easily with
this professional quality twopass assembler. Uses
Zilog mnemonics with labels and symbols, 8
pseudoops, syntax checking, display or print
listing with commands. Debugger includes
examine/modifying, breakpoint with register
display, line renumbering occupies 7K. Com-
prehensive multipage manual.

Memotech
Memopak Assembler
EPROM: $49.95 plus $4.95.

Code and edit a source program in Z80
language and then assemble it into machine
code. Editor mode allows you to code directly
in the right format, manipulate individual lines,

July/August 1983 9 SYNC

and control the exact placing of source and
machine code. Routines may be merged or
listed. Handles all standard Z80 mnemonics;
numbers in hex or decimal; comments; and
user-selected labels. On EPROM and plugs
directly into your computer.

Nanos Systems Corp.
ZX80, ZX81, and Timex/Sinclair 1000 System
Reference Card. $5.95.

Quick summary reference card with: Graph-
ics, Basic statements, Basic commands, Basic
functions and derived functions, special char-
acters and operators, screen layout, all codes
panels (0-255), selected ROM calls, tips on using
FOR-NEXT, IF-THEN statements, ZX80 and
ZX81 memory maps, error codes, Z80 timing
chart, short version of Z80 language, entire Z80
language OP-CODE. Accordian style card with
20 pages on 10 panels.

G. Russell - Electronics
Key Load
16K RAM. Cassette: $10.

Using Your Computer:
Programs

Astronomy

Bug-Byte Software
Constellation
16K RAM. Cassette: £8.

Turn your ZX81 into a telescope. Program
produces a simulation of the night sky as seen
from any position on Earth at any chosen time
this century. Point your telescope in any dir-
ection, more it around, zoom in or out. Stars
displayed by magnitude or constellation.

Gladstone
Solar System (Z44)
16K RAM. Cassette: $11.95.

A databank on the cosmos. Facts, interre-
lationships of the planets, their moons, the sun,
artificial satellites, the constellations.

Kamel Technology

All 3 astronomy programs for $24.95.
Planetfinder
16K RAM. Cassette: $9.95.

Computes the right ascension and declination,
constellation planet is in, brightness, distance
from earth, angular diameter, and phase. For
any planet, any date.

Suntracker
16K RAM. Cassette: $9.95.

Computes position of sun, sunrise, sunset for
any location, any time.

Moontracker
16K RAM. Cassette: $9.95.

Computes position of moon, rising and setting,
for any location, any time.

SINWARE provides these quality
machine code programs for the ZX81/
TS 1000:

STEP

STEP provides line-at-a-time execu-
tion of your BASIC programs and
shows you the display and variable
values to pinpoint programming er-
rors. Set line breakpoints, loop break-
points, or conditional breaks for fast
testing of long routines. STEP oc-
Cupies 3K at the top of your 16K RAM
as you write and test new programs.
Detailed documentation. The final
solution for BASIC bugs.

Z- TOOLS

Z-TOOLS lets you merge programs
from tape, renumber lines (including
GOTOs and GOSUBs) for neat listings,
copy and delete program blocks for
quick restructuring, or verify tape con-
tents against memory to eliminate pro-
gram losses. Supplied in two versions,
for the top of a 16K RAM pack or for
the 8-10K block of expanded RAM.

HOT Z

HOT Z disassembles, debugs, and lets
you copy and edit machine code pro-
grams. If you can move a cursor
around and understand hex numbers,
you can use HOT Z almost at once.
Provides beautiful assembly listings,
addressable cassette functions, runs
your ZX printer (or Memotech 1/F),
even disassembles the ZX floating-
point language. You owe your ZX/TX
a fresh dose of HOT Z.

Z EXTRA

Z EXTRA is a display manager and
data filer that lets you enter text, data
or pictures directly to the screen and
save them in groups in memory, on
tape or in print. Display them sequenti-
ally or in scrolls through one another or
use them in your BASIC programs.
Give your computer a completely new
personality with Z EXTRA.

PRICES Add $2.00 for postage
STER... uium Cassette $14.95
Z-TOOLS r zn Cassette $14.95
CEXTRA... vvv Cassette $19.95
HOTZ...16K or 32K + Cassette $19.95
HOT Z-E....Four2716 EPROMs $40.00
SINWARE
Box 8032
Santa Fe, NM 87504

101

cottage
technology

ZX81/TS 1000 HARDWARE

REVERSE VIDEO—Convert your TIMEX/ Sinclair
to the standard white letters on a dark background
for better readability and a more professional ap-
pearance. Fits inside case with only 4 solder con-
nections. $10.95

VIDEO MONITOR OUTPUT—A small pigtail
allows you to connect your TIMEX/ Sinclair to a
NTSC-compatible standard video monitor for a
crystal clear display. Parts and instructions. $4.95

Ese} THE LAST CASSETTE/16K Fix—Having pro-
blems with SAVE/LOAD when the 16K module is
attached? This small modification reduces ram
pack noise at the signal source. Kit and instruc-
tions. $2.95

ZX81/TS SOFTWARE

ACZ GENERAL LEDGER—Computerize your
small business accounting. This system prepares a
full set of financial statements and keeps a record
of the ledger transactions. It can handle any com-
bination of up to 400 entries and accounts per ses-
sion, sorts 150 entries in 10 seconds, and works
with or without a printer. 16K. $29.95

ACZ CHECK REGISTER—Does more than just
balance your checkbook. It summarizes expenses
by account so it’s easy to see just where your
money is going. This program can be used alone,
or as a companion to the ACZ General Ledger. 16K.

$10.95

ACZ EASY GRAPH takes the tedium out of bar
graph preparation. It automatically calculates the
correct scale, offers continuous updates, and
stores 4 different graphs in one program. 16K.
$9.95

YOU'RE THE BOSS—A business game. As
president of your own company, you make the pro-
duction and marketing decisions that lead to suc-
cess or bankruptcy. A strategy game for 1 or 2
players. 16K. $10.95

IMPROVE YOUR PROGRAMMING

Looking for ways to improve your BASIC program-
ring techniques? We've listed 10 of our best
routines with examples of how to use them in your
wes programs. One routine makes it ‘‘impossible’’ to
enter the wrong data. Another aligns columns of
numbers by the decimal point. Others allow single
keystroke menu selection, sorting, rounding, and

. $4.95 or FREE
with any software purchase.

snb QUE QD uM QUD OH QI VPN E E GEcHS M ut e

COTTAGE TECHNOLOGY
5720 W. Little York, Suite 178
Houston, TX 77091

REVERSE VIDEO

ACZ GENERAL LEDGER ;
ACZ CHECK REGISTER ;
ACZ EASY GRAPH
YOU'RE THE BOSS

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Robert C. Moler
Astro-Utilities
16K RAM. Cassette: $14.95.

For amateur astronomers. Calculates Julian
date, siderial time; rise/set times; altitude/
azimuth; procession of celestial objects; and
more. Menu driven; instructions.

Orbit
16K RAM. Cassette: $9.95.

An astronomical demonstration program for
educators. Draws elliptical orbit shapes based
on eccentricity. Also calculates and produces
animated display of orbital motion.
Instructions.

Galaxy
16K RAM. Cassette: $9.95.

An astronomical demonstration program for
educators. Draws normal and barred spiral gal-
axies from input parameters. Galaxies may have
variable orientation from face-on to edge-on.
Choice of two spiral algorithms. Instructions.

Relativity
16K RAM. Cassette: $11.95.

An astronomical demonstration program for
educators. Graphically shows effects of relativ-
istic velocities on length of a spacecraft plus
time dilation effects. Demonstrates the “twin
paradox” on trips to Alpha Centauri and the
Andromeda Galaxy. Instructions.

Planets
16K RAM. Cassette: $9.95.

An astronomical demonstration program for
educators. Calculates and displays positions of
the planets around the sun for a date or series of
dates. Can plot planet distances to scale and
include a comet. Instructions.

Print-Planets
16K RAM. Cassette: $11.95.

An astronomical demonstration program
which uses the hi-res capabilities of the ZX
printer to plot the positions of the planets in
their orbits. Menu driven with 4 plotting options.
Orbits are delineated and planets are plotted
with their astronomical symbols. Instructions.

Bob Woish
Telescope Design
2K RAM. Cassette: $4.95; listing: $2.95.

Asks for desired objective diameter and
f/ratio, inputs physical dimensions and optical
data for a Newtonian reflector optical assembly.
Saves hours of calculation.

Z-West

Celestial Locator

16K RAM. Cassette: $7.95 plus $1 s/h.
Provides the amateur astronomer with

AZ/ALT positions for any given celestial

source. Radio astronomers can rapidly adjust

antennas with the location positions provided

by this program. Celestial Locator/ZX99 is also

available with this tape to printout monthly

positions on RS232 printers.

Graphics

Biocal Software

(See Directory of Suppliers for prices.)
Display

Several different graphics techniques are used
to create pictures and plots.

Skeet. 1K RAM.
Turn your computer into a drawing board.
Visible flashing cursor even while retracing.

Computer Software Associates
Graphics Starter Pack
1K RAM. $14.95.

4 programs: Kaleidoscope, Large Print,
Medium Print, Draw-A-Picture. Explains and
discusses GOSUB, INKEY, PRINT AT, PLOT
and UNPLOT, the way the ZX81 stores char-
acter shapes (and where), the decomposition of
the decimal to binary and how to use the cursor
to “draw” on the screen.

Multigraphics 2.3
16K RAM. $14.95.

Menu-driven package gives full control of
ZX81 graphics. Includes: Comprehensive
sketch pad function, small, large and jumbo text
functions. Two packages of mixed graphic and
text displays or one animated display. Edu-
cational/tutorial, business graphics functions for
shop-window advertising displays.

Ksoft

TS-Art

16K RAM. Cassette: $12.95 (s&h: $1.50 U.S.,
$2.50 abroad).

Graphics program and Logo-style educational
tool. Indirectly teaches concepts in arithmetic,
geometry, and computer science. Work with a
pencil, eraser, about 120 brushes, a video in-
verser and a “flicker” by moving them in 8
directions or along circles and lines. Set any
background. Define new graphics commands.
Expand, compress, or rotate. Save or print art-
work.

Memory Master
Instant Art
16K RAM. $10.95 pp.

“Paint” pictures on the screen using two brush
sizes and three colors (black, white, and gray).
Paint in 8 directions and change brush size or
color at any time with a press of a key. Directions
contain a simple, single line change which allows
you to paint with any character on the keyboard.
Option for painting random symmetrical pat-
terns.

Data Entry/Retrieval

Biocal Software

(See Directory of Suppliers for prices.)
Catalog

Card file system. Uses indexed sequential
access method (ISAM). Vary key and record
sizes.

Clients

Mailing list keeps track of your clients using
ISAM techniques to maintain the file. Sales/
Dates.

Histogram
Category maintenance, transact data entry,
category plots, totals, and averages per cate-

gory.

ISAM

Indexed Sequential Access Method subrou-
tines allow you to retrieve your records via
alphanumeric keys.

Sfi

Actual Screen Copy
of VOTEM In Action

The y-axis is temperature in
degrees C. The x-axis is
time. Each unit equals 5
seconds. The graph starts
with the temperature probe
in ice water. At time=9 the
probe was placed in air at
room temperature. At
time=25 the probe was
placed in a cup of hot water
and at time=31 the probe
was again placed in air at
room temperature. The
program used only 2K of
memory. Imagine what you
could do with 16K!

WE ALSO HAVE THE
HUNTER BATTERY
BACK-UP MEMORY

e Up to 8K of nonvolatile
memory

e 6116 CMOS RAM or
2716/32 EPROM

Complete kit
with 2K $29.95
Assembled with

8K $59.95
Shipping (memory
only) $ 1.95

Down East Computers
PO Box 3096
Greenville, NC 27834

July/August 1983 ° SYNC

Library
Keep track of your books. Search list for
author, title, publisher.

Orders
Order tracking system with mailing list, main-
tenance, sort, report, plot.

Reminder

Calendar and appointment book. Make, can-
cel, change, list appointments. Uses ISAM file
technique.

L. Harmon
Mail Master
16K RAM. Cassette: $6.95.

Mailing list program. Menu-driven; auto run.
Includes full edit and search routines. Supports
any ZX/TS compatible printer. Options include:
add names, search/view, edit, search/print,
prints complete list, inform, and others. Com-
prehensive user’s manual.

Data Master
16K RAM. Cassette: $6.95.

Versatile data storage/retrieval program. In-
cludes full edit and search routines. Supports
any ZX/TS compatible printer. Ideal for the
small businessman or homeowner. Includes
comprehensive user’s manual.

Chart Master
16K RAM. Cassette: $6.95.

Program generates and analyzes bar charts.
Printed output if desired. Ideal for the small
businessman or homeowner. Includes full in-
structions.

Silicon Valley North

Grade Roster

16K RAM. Cassette: $7.95 plus $1 s&h.
Complete permanent gradebook exam and

course performance analyzer. High capacity.

Scores displayed in table with analysis of mean,

standard deviation, variance, high/low score,

frequency distribution for each activity. Final

or part term student rankings based on weighted

exam scores. Plus other useful options.

Stuart Software
Press Release Mailing List. $25.

1-Across mailing labels in Zip Code order.
Mailing list for sending out press releases for
computer-related products. Contains about 400
periodicals. Ideal for businesses seeking to max-
imize the “free advertising” which occurs when
a press release is printed in the “New Products”
section of a magazine or newsletter.

Financial

Biocal Software

(See Directory of Suppliers for prices.)
Bar-Chart

Watch the fluctuations in your expenses. Plots
numeric arrays using a scaled histogram.

Checkbook. 16K RAM.
Balance your checkbook. Outstanding
checks, deposits, current balance.

Loan
Generates loan payment schedules. Check
interest vs. principal. Evaluate time payments.

—

VW. m
qnani sate

PICK OF THE CROP FOR 16K!

PROGRAMMING
mE C) FORM PADS

- * All lines including edit lines
EI * Not half sheet—full 82x11
seo premium erasable paper
: ZA * 50 sheets per pad
\ baer X iai * Free coded example of
| oe Tl W.C. Fields
* Window Card for easy reading

.19 ea. (+ .75/pad P&H)

Zxak-man!
At last a version with attention to detail. Zxak
is a cute cubical character that winks and
chews as he moves. 5 levels and 4 ghouls
make for strategy game playing. All in smooth
M.C. animation. A must ............ 14.95
XON!
'81
or
1000

City of Xon!

Scrolls 3 dimensionally. Your shadow follows
below as you avoid hazards. Various
weaponry help you rack up points. Most

impressive graphics your machine can WR
OXIDE TIMES, Ier eive. 19.95 y^ ETA
Please add 1.50 per cassette postage & handling “¢

GRAPHICS A to Z

This invaluable manual concentrates on graphic
programming. For novice or pro with 81/1000 or
Memotech's HRG there's something exciting:

For '81/1000 For HRG

e 3-D Drawing € Terms dictionary

e Shapes @ Plot 3-D (cover)

è M.C. listings | z= See the screen fill 34x)

e Printbelow | “ig € HRG disassembly
or to right § e New call addresses
of display!

Many techniques for Basic programs. Later chapters take you
carefully into Machine Code. Tired of pulling your hair out over
other Machine Code texts? These chapters are well-written
with simple examples to get you into the world of fast graphics
UM DOR UNES Med han | okay MES CE s 17.95 ppd

INN E Tdi? :
x3 pleasan[rees

Pleasantrees NAME
Programming WA sos
x wn
Tucson, AZ 85741 IPIE IRL NIME SIE ee ee J
ut UF Nt Fu iu LALLY Danas
103

LOVE AT

FIRST BYTE

C-20 Magazine has something -

for every TS-1000 or ZX-81

offer 2K and 16K programs in
each issue.
Educational software.
Software for your Home
Games Games Games |
Editorial Section —
The C-20 Mailbox —
A Big Time Saving Value. Less
than $4.99 per issue with over 75
programs per year. That's less
than 80 cents per program! .

C-20 Magazine comes each

month with ready to run soft-
ware. Notime wasted typing ina
program listing. |

1 Year (12 issues) ..... $59.95
6 Months (6 issues)
Kansas residents add 3%. First
class mail included in North

America. All others add $10 pet :

subscription.

P.O. Box 3801
Wichita, Ks. 67201-3801

24 Hr. Toll Free Order Line
1-800-835-2246 Ext. 240
or in Kansas |
1-800-362-2421 Ext. 240
VISA and MasterCard

Dealer Inquiries Invited

. 38 95

( -20. reget gente ;

Sales

Inventory sales analysis shows you what is
selling best, how many were sold, and total sales
dollars.

Markel Software
Deduc-table
48K RAM. Cassette: $14.95.

A menu driven program to track a year’s
worth of tax deductions. Twenty user defined
categories. Each category may contain 25
entries. Entries include date, description (com-
ments), and dollar amounts. Review individual
files, or totals Y.T.D. Self-starting, self-naming,
self-saving. Full support by SASE.

Free Update

Current owners of Financial Record Keeper
(16K) or Financial Record Keeper Plus (48K)
may write for listing of newly added Tax De-
duction Review application to flag tax deduc-
table payments during the normal entry pro-
cedure and review them at any given time. (Note:
Current cassettes being mailed incorporate this
application.) Send SASE.

Home Budget Planner
16K RAM. $10.95 pp.

Computes and compares amount spent versus
budget for a 13 month period. 20 user definable
budget categories and 10 separate categories
for income and deductions. Displays and prints
out data by the month or year to date. Bar
charts are drawn from monthly averages and
show the year at a glance in graphic detail.
Menu driven with easy edit and update.

Memotech
Memocalc
EPROM: $49.95 plus $4.95.

Spreadsheet analysis to assist with reports
and financial forecasts. Performs complex num-
ber crunching routines with ease. Memopak's
64K RAM gives a table of up to 7000 numbers
with up to 250 rows or 99 columns. Quick
revisions. The CALCULATE command reeval-
uates and displays the information. Tool has
been generalized to perform interactive calcu-
lations in numerical tasks. On EPROM and plugs
directly into your computer.

Sikes Software
Checkmaster
16K RAM. Cassette: $16.95.

Enter and store over 450 transactions per
load. Menu driven. Allows you to list, search,
add, save, graph. Special graph feature allows
you to graph checking balance 9 dates at a time,
starting with any desired date. Search for credits,
dates, and debts. Graph may be scaled and
labeled as desired.

Stocks

Air Capitol Software
Call/Put Stock Options Analysis
16K RAM. Cassette: $25.

Make objective strategy decisions. Requires
only current options data from popular financial
publications. In-depth analysis using extension
of Black-Scholes model. Nine options per run
ranked by potential profit, loss, expected return.
Easy-to-use; full screen edit. Documentation.

Biocal Software

(See Directory of Suppliers for prices.)
Stock. Cassette only.

Learn the mechanisms behind the stock mar-
ket. Includes buying on margin, short selling,
convertible preferred, options to buy via war-
rants. Invest.

Memory Master
Stock Analysis and Portfolio
16K RAM. Cassette: $10.95 pp.

2 programs: Program 1: Takes data on any
stock, computes total cost including broker's
commission, and computes the result of any
number of call options entered including gain,
yield, time held and more. Program 2: Holds
information on up to 10 stocks and computes
gain, yield, etc. Displays a composite view of all
stocks held. Easily updated, changed, or
deleted.

Word Processing

Bob Fingerle

Textwriter 1000

16K RAM. Cassette: $11.95; listing: $5.95.
Text editing program. Capabilities include:

insert/delete, text compression/realignment, |

and buffer memory for saving portions of text to

use elsewhere. Also includes tabulation, logi-

cally formatted display, text save, and ZX/TS

printer control. SASE for free information.

Memotech
Memotext
EPROM: $49.95 plus $4.95.

Brings commercial standards of text editing
to your computer. Text is first arranged in 32
character lines for the screen with comprehen- .
sive editing facilities. User chooses line length
for printing and the system does the rest. Memo-
tech printer interfaces enable output with 80
character lines, upper and lower case, single
and double size characters. On EPROM and
plugs directly into your computer.

Miscellaneous Programs

John Richard Coffey
Touch Type Game
2K RAM. Listing: $1 plus long SASE.

Learn to touch type all the ZX/TS symbols in
a fun, challenging manner. Recommended only
for users with special keyboards or overlays.
Takes about 10 hours to master. All Basic. More
detailed than the game that appeared in SYNC.

Computer Software Associates
Statistics Package
IK RAM. $12.95.

4 programs with error-correcting facilities to
compute the following statistics: mean, standard
deviation, variance, correlation coefficient, re-
gression, equation, confidence interval for
mean, 3 applications of the “t” test and the “F”
test of the ratio between independent sample
variances.

Compuwiz Software
The Educator
16K RAM. Cassette: $10.

A program to teach you all about program-
ming your computer. All teaching is interactive
and very easy to learn.

HORIZON

SIMULATION

TS/1006
o-oo 1

FOR YOUR COMPUTER.
EDUCATION

GAMES ETC.

FOR A FREE CATALOG AND FREE
PROGRAM LISTINGS, URITE-

1983 Directory

* Where to find: Disk Drives, RAM Extensions, Print-
ers, Modems, Keyboards, Game & Serious Soft-
ware, Books, Periodicals, Programming Aids, and
other Exciting Accessories! `

* Articles on: Special applications like Control Cir-
cuitry, Enhanced Graphics, Voice Generation, Music
Synthesis, Video Inversion, Light Pens, Joysticks,
etc. j

* Complete Descriptions: We'll tell you what it is,
what it does, how much it costs, and where to
buy it.

* Jam-packed w/photographs: We knew you'd
want to see what these products look like. So, we
got pictures and put them in!

Only $5.95 ... Postpaid!

Sent First Class in the U.S.A.
To Order: Send check, money order, or VISA/MC
number and expiration date. MN residents add 696
sales tax.
Dealer Inquiries Welcome.

E. Arthur Brown Company

Dept. ZA-3 1702 Oak Knoll Drive
Alexandria, MN 56308 Ph: 612/762-8847

PREVENT

erratic operation. A
support designed for your
Sinclair 16K memory stops
the white outs. The
support mounts on your
Sinclair ZX81,1000 case.
Send for complete kit

$4.75 POSTPAID

Check or money order
TO
THE FOURTH DESIGN
PO. BOX 1406
NIAGARA FALLS, N.Y. 14302

Florida Creations
Music /Sounds Package
IK RAM. Listing: $3.

5 programs and discussion for broadcasting
music and spaceship noises to a nearby radio.
No hardware modifications required. Controls

the radio frequency interference generated by
the computer.

Home Applications
Weight-Watcher
Listing: $3.

Basic program contains database of 200 foods
and caloric values by portion with more than 30
common activities to compute minimum daily
requirements. Compare daily consumption as a
dieting aid. Program can be tailored for personal

diets or food preferences. Completely menu
driven. !

Enjoying Your
Computer: Games
Miscellaneous Games

Biocal Software

(See Directory of Suppliers for prices.)
Chase. 1K RAM. |

Flower i

Display program plots ellipses in a spiral
pattern. Watch as many varieties bloom.

Fvee. 1K RAM.

A road racing game. Steer your formula car
to a new distance record.

Guess

2 games in 1. Hangman plus Guess the Animal.
A self-learning game in which the computer
questions you.

Hollywood. Cassette only.
As a movie produce you must obtain actors,

script, and a director. Spending money begets
money.

Life
Watch colonies of life-forms become alive,

mutate, and die. Control matrix size, genera-
tions. :

Meelborn. Cassette only.

Two cars race toward a 1000 mile goal. In-
cludes flat tires, accidents, running out of gas,
stop lights.

Pong. 1K RAM.
Two player pong game. Keeps score.

Quicksand
You are traveling through a forest and must

detour through a swamp. Can you avoid the
quicksand pits?

Race. 2K RAM.

A road race game. Can you break the distance
record?

Roadrace

Steer a Formula-1 car through a tough road
course. Different track each time.

SyncMaster

has the programs for
your Timex-Sinclair

1. VU-WRITE TEXT EDITOR

| implifi tool to
e Word processing simplified e Perfect
document spreadsheets and programs $ Send
letters, notes on cassettes * 11K available to
add, insert, delete, move text e Up to 348 lines
of 32 characters in 16K.

2. DECISION MAKING

e Sophisticated approach to computer-aided
decision making, based on recent university
research e Breaks down multiple problems into
manageable sets, making decisions aS yOu
would.

3. DATA MASTER 16-64K

e Uses all memory available if needed © Keeps
track of any kind of data you want with custom
searches, sorts and reports e Get what you need
from the computer, much easier than program-
ming.

4. GRADE BOOK

e Teachers: cut a 3-hour job down to size . . .
io nud Keep track of up to 50 students,
with up to 30 grades per student * Unlimited
classes e Weight grades any way possible, us-
ing your own formulae.

5. STAT MASTER

e Written by a statistics user for other users *
AA n pit useful descriptive operations on
your custom-designed data files * Variances,
co-variance, standard deviation, standard error,
chi-square, hypothesis testing, confidence inter-
vals, all means.

6. BUSINESS START-UP PAK #1

° ou want to start a business! * Here are
Sh weet programs which provide information
you will need to know but which most people ig-
nore e Break even with direct and variable costs;
how much you need to sell to get your money
back; help find true costs * Pay Back — should
you buy that piece of equipment? Now it's an
easy question. e How long will it take to make a
profit on it?

7. FINANCIAL ANALYZER

i i incipal
e Save big $$$ on prepaying mortgage principa
e What wil your IRA be worth in the year 2000?
e What was the real yield on that investment? e
Simplify all standard interest rate calculations.

8. YEARLY DATEBOOK

e Never forget an important date again, 1.6. E:
surance premiums due, anniversaries, etc.
List once a month for all needed dates *
Calculate day of week from date.

9. INSURANCE RECORDS

: i household,
e Complete record-keeping of :
business belongings, !.e.. jewelry, electronic
equipment, credit cards, collectibles, everything
e Use to help.insurance agent recover after a fire
or burglary.

10. SCREEN MACHINE

° input prompts anywhere on screen
dba Delon s Canoe error checking,
formatting and verification e In MC for absolutely
no screen flicker e Make your screen 100%
neater and more professional * Commercial
rights available.

All programs require 16K

Each Cassette $1 495 plus $1 postage

Send $1 for Catalog

$2 for any manual plus catalog; payment credited to first order.

- call TOLL FREE
USE VISA or MC; cal
1/800/334-0854, Ext. 888

IN NORTH CAROLINA CALL
SyncMaster

919/643-7120
p.0. Box 511, Oak Ridge, N.

C. 27310

We're looking for programs in all fields. We
will publish your programs, paying top
royalties to you, if your programs are the best
in their field and truly useful.

105

SAVINGS x SAVINGS

We are offering quality programs for
the Timex-Sinclair and ZX81 computers
written in Canada and sold at
Canadian prices.

For the Canadian purchaser, there is

mo duty, Excise tax or currency
xchange»
For all other programers, there is a

savings of 20% or wore when you send
a money order in Canadian Currency,
Send one dollar for our catalog of
programs and we will subtract that
from your first order,

SOPHIA SYSTEMS
15122 Pheasant Drive
Surrey, B.C. Canada, VƏR 4X4

TIMEX-SINCLAIR

TS1000 TS1500 TS2000

Memocalc Spreadsheet (16-64 K)
Memotext Word Processor (16-64K)
MemoAssembler (16-64K)
TIMEX-Sinclair “1500” Computer......... $74.95
TIMEX-Sinclair "2000" Color Computer
$148.95,
TIMEX-Sinclair 2040 Printer
Seikosha 80 Char. Printer Pkg
(Incl. Parallel Interface & Cable)

Memopak 16, 32, 64K RAM

$48.95, $89.95, $138.95
Basicare 4 Megabyte System Call or Write
Q-Save, Load/Save 6 Times Faster
Memotech Keyboard

To Order: Send check. money order. or VISA/
MC numberandexp. date plusS2.00 shippingin
the USA. MN res. add 69» sales tax.

Write For Our Colorful New Catalog!

E. Arthur Brown Company
Division SM-3 1702 Oak Knoll Drive
Alexandria, MN 56308 Ph. 612/762-8847

KEYBOARD
FOR YOUR
TIMEX-SINCLAIR.

Full-size contoured keyboard
Sturdy aluminum chassis
48 sculptured keys
No soldering

599"

Permanent Sinclair-Timex legends on keys e
Full-size advance bar (<>) è Individual keys
for $ $ » EDIT DELETE e Shift lock e On-
off switch e Optional numeric keypad © Op-
tional aluminum case that holds TS1000 and
RAMpacks Imo

LE |
INC

119 Peter St. No. 6
Union City, NJ 07087
(201) 864-4410
Send for free catalog Dealer inquiries invited.
Charge cards accepted, American Express, Visa or

106

Secrets
Cryptographers. Code/decode messages with
a keyword generated cipher.

Shark-Hunt
Chase a man-eating shark; trap it in your
nets; avoid the rocks, old tires, and other snags.

Snare
Corral a wild stallion. Try to encircle him in
the minimum number of moves.

Tower. 1K RAM.
Guessing game. Code demonstrates poking
the internal display file.

War
Inverse video graphics display program which
plots a multiplayer card game.

Worm
Graphic display program. Plots a worm’s path
as it searches for entry into the ground.

Computer Software Associates
Towers Of Brahama
1K RAM. $9.95.

Challenges your skill and manipulation. There
are 3 posts on the screen. Your starting base
contains 5 disks stacked in ascending order by
size. The remaining 2 are parking bases. To win
this game, you must park the 5 disks on the third
post in an ascending order.

Bulls and Cows
1K RAM. $9.95.

A game of concentration for all ages! The
computer randomly chooses 4 numbers. You
must decipher the “master set” exactly. When
you enter your guesses, the computer will tell
you how many of the chosen numbers match
the set, and how many match in exact order.

Nim
16K RAM. $9.95.

The first player chooses a number of matches
and arranges them in 3 piles. The second player
then chooses a pile and removes some matches.
The first player then removes some matches.
Any number of matches may be removed from
any pile. The winner is the person (or computer)
who removes the very last match. 4 levels of
difficulty.

Four in a Row
16K RAM. $14.95.

A game for 2 or more players on a vertical
board with 8 columns and 8 rows. The object is
to get 4 pieces in a row: horizontally, vertically,
or diagonally. Players alternate turns until a win
is achieved.

Slides and Ladders
16K RAM. $14.95.

Up to 4 players. Each player begins in the
cellar of a mansion and must work his way
through 40 rooms. The player to reach the 40th
room first is the winner.

Mugsy
16K RAM. $9.95.

You are the Boss of a Chicago gang operating
a protection racket. Can you survive the rival
gangs, the cops, and Nick the Greek?

Intercomputer Inc.
Hopper (1017)
16K RAM. $12.95.

Can you help Fergy and his friends get across
the highway and back to the lily pond? Includes
crocodiles, logs, varying speed traffic, etc.

Memory Master
Code Master
16K RAM. $10.95 pp.

Menu allows 3 choices: 1) solve cryptoquotes
stored in memory; 2) have the computer gener-
ate a code from material typed in by the user; or
3) solve a code from a newspaper, etc. Options 1
and 2 offer 3 different types of code, each with a
different level of difficulty. A cursor controlled
control panel is used for letter replacement.
Hint and quit routines make it easy enough for a
10 year old to master but hard enough for the
avid puzzle fan.

MicroSync Software
Air Traffic
2K RAM. Cassette: $4 plus $1 s&h; listing: $2
plus SASE.

Try to dodge the oncoming planes and build-
ings. Many levels of play. Keeps score. Fast
action.

Praise Data Systems
Bible Quiz Games
16K RAM. Cassette: $10.95 pp.

A series of games to test your knowledge of
Bible Scripture. Interesting and educational fun
for the whole family. Keeps score for you so
that you can see your progress as you play
again. SASE for list of programs.

SyncWare Co.
Storm Lander
16K RAM. $9.95.

Make an emergency landing at Denver's
Stapleton Airport in your commercial airliner,
during a thunderstorm. Three screens of graph-
ics show your progress in avoiding storm clouds,
other aircraft, mountains, and downtown Den-
ver, while homing in on navigation beams for a
safe descent to the runway and finally taxiing to
the terminal.

Miner s Revenge
16K RAM. $9.95.

Get fabulously rich if you crack the mother-
load. The old miner's last will, will help you on
the way, equipped with a pick-axe, flares, spikes,
and a lantern. The 9 markers left by the old
miner will guide you to the big vein, but watch
out for falls that cause the loss of time and tools.
Not a text adventure game; continuous full
screen graphics for improved realism.

Super Slide
16K RAM. $9.95.

You are in the 1988 Olympics bobsled event.
Pick up points while avoiding skid-patches,
walls, ruts, and the course boundary. If you pass
the qualifying run, you compete in two heats.
Your score on both runs places your final posi-
tion in a field of over 80 competitors. You must
be very good to win the gold medal. Practice in
the DEMO mode, which continually cycles a
new course. Machine code action.

Sikes Software
Mega-tron
16K RAM. Cassette: $14.95.
Try to destroy the computer light cycle. Avoid

July/August 1983 ° SYNC

hitting the light trails left behind the cycles, the
walls of the game grid, and the cycles themselves.
On screen scoring and bonus cycles. Machine
Code.

Skelly Computing

Guess It
16K RAM. Cassette: $3 plus $1 s&h; listing: $1
plus SASE.

A number game with 3 levels of play and
prompting.

2-Bit Software
Working Mother s Dilemma
2K RAM. Cassette: $14.95.

Package of 4 games: Designed as a fun way
for women to learn about computers: Mad Dash:
Tests your ability to race through the house
when you have not had a break all day. Carfool:
Figure out how to use the least amount of gas
while running errands all over town. Harried
Housewife: Adventure game that rewards you
with a hot bath and a nap after a hectic day that
includes a dazed search for your car in the
parking lot of Shopping Mall.

Shoot 'em Up Games

Biocal Software

(See Directory of Suppliers for prices.)
6-Shooter

A game of skill in which you try to hit a
randomly moving target. 5 levels of difficulty.

Artillery

Protect your hometown from enemy planes.
Variable gun angles, limited ammo, so aim care-
fully.

Bomber

Maneuver your bomber through anti-aircraft
flak to drop your payload over the target; fuel
limit.

Dogfight
Shoot down the enemy planes before they
destroy your 5 planes. Fuel and ammo limits.

Sniper. 1K RAM.
A randomly moving target pops in and out of
view. Hit it before it disappears.

Wolfpack

You are the commander of a Navy destroyer
searching for enemy submarines. Depth charges
ready.

Computer Software Associates
Murgatroyds Revenge
16K RAM. $14.95.

The fiendish Murgatroyds are on the warpath
again! You must fight off their attack with mines,
superglue, decoys and more.

Robot Tanks
16K RAM. $14.95.

The battle has gone poorly. Enemy tanks
have you surrounded with an unlimited supply
of ammunition. You have one shot left. After
you have fired your final round, your tank will
become immobile. Your only source of defense
is to lure your enemies into shooting one
another. Good luck! Save your last shot to win!

July/August 1983 9 SYNC

MicroSync Software
Bomber
2K RAM. Cassette: $3 plus $1 s&h, listing: $1
plus SASE.

A target practice game in which you try to hit
a target on the bottom of the screen. 2 types of
missiles, one bomb. Target explodes when hit.

Robert J. Midura
Strategy at Sea
16K RAM. Cassette: $10.

2 games. Convoy: Shooting gallery type game;
your sub has 20 missiles to attack a 15 ship
convoy; targets pass in either direction at various
distances from your sub; graphic explosions; 5
levels of play; 5 types of ships; score shows all
ships sunk. Sub Hunt: Your destroyer must
track down and sink 5 nearly invisible subs
before they sink your 5 fleet ships or your
destoyer; watch out for mines and collisions
with your own ships; graphics display of ocean
grid, fleet ships, mines, depth charges, and ex-
plosions.

Space Games

Biocal Software

(See Directory of Suppliers for prices.)
Cruiser

Navigate your spaceship through a meteor
storm. How far can you travel without damage?

Orbit
Maneuver your spaceship into an inner orbit
to pick up your cargo.

Treasure
Collect the treasure before the alien robot
catches you with its radar tracking system.

Computer Software Associates
Galactic Patrol
16K RAM. $14.95.

Your 6 year mission is to explore new worlds,
to go where no being has gone before! Your job,
as captain of the Galactic, is to protect the lives
of the 500 aboard and to operate the bridge.

Super Invaders
16K RAM. $14.95.

Negotiations have ended. Now comes a show
of strength. “The Earth is being invaded!” All
beings on Earth are depending on you. Don't let
us down!

Intercomputer Inc.
Arcade Games (FG1016)
16K RAM. $12.95.

In any other time or galaxy, the dust ball of
the world called Tai would have been quite
unimportant. Time changes and the entire civ-
ilization will be betrayed. You have been chosen
to defend Tai. The galactic future depends on
you.

Memory Master
Spaceflash
16K RAM. $10.95 pp.

Earn shots at an alien landing craft by suc-
cessfully answering questions in various drills. 3
levels of drill in addition, subtraction, multipli-
cation, division, and visual memory training.
Complete scoring for drills and space game.
The visual memory drill automatically increases
in difficulty as the player gives correct
responses.

Tactile Feedback Over lay

For: ZX 80/81, Timex 1000, or Microace
** TOUCH TYPING POSSIBLE
** STOP MISSED KEYS
** SPEED ENTERING PROGRAMS
With our easy to install keyboard overlay
3.95

16K Software fo

ZX FROGGIE An excellent version of the
arcade game. Frogzie must cross the busy
highway and hop the logs to get home. Full
screen moving graphics, fast m/c action, 4
levels, different screens and speeds. Name
and SAVE three best scores. ------- $14.50

DRAGON HUNT A maze game played in Dragon |
Caves. You must find & slay 3 dragons.There
are 15 arrows and a magic sword to help you
survive the hidden dangers. ------- $12.50

WORD SINC A word processor for the Sinclair
or other 32 col. printer. Fast m/c inserts
variables, lists, moves and justifies. 9000
characters with 16K, is easily expandable.

Menu controlled.With instructions.- $12.50

Four 16K Programs on One Cassette
MATH TUTOR Add,subtract,multiply & divide.
Five levels in each. Menu controlled.
TYPING SKILLS A fun and competitive skill
improver.Set speed, keep up to the computer
BI Guide missiles to intercept the Bird
or what it drops will bring a nasty end.
ASTRO SMASHER Dodge asteroids, smash enemy
ships before force shields fail. -- $12.50
U.S. Orders to: P.Hargrave, Site V, RR bà,
Nanaimo, B.C., Canada V9R 5X9

81 Ti

SERIOUS PROGRAMMERS

"MUST-HAVE" UTILITIES
For ZX-81 and T/S 1000 Computers
SEI R RNE E = SST PRR SARE TE PT IN ONERE QR RN

FILE*SYS $10
Read/Write Cassette Data Tape Files
(fast, flexible, reliable)
FILE*BASIC
Save/Merge/Erase BASIC Segments
(includes FILE*SYS functions)
FILE*VARS $5
Save/Restore Strings & Arrays
(requires FILE*SYS or FILE*BASIC)
BASIC*OLAY
Overlay/Copy BASIC Segments
(permits full use of 64K RAM)

$15

$10

Simple user interface via USR function
Well-documented user manuals

Available on tape cassette in relocatable machine lang.
DCUM Tee Aa ioca oec cam uude eaa o a Tu TDI LTD LER ee RECUERDE NEN

SASE for info Check or MO delivers now

eb
Sirus Ware

6 Turning Mill Road
Lexington, MA 02173

Mal E. r

(Matrix Operations Programming
System)

The power of linear algebra
at your finger tips. Specially
designed for college students,
Scientists and professionals.
Multiple applications to solve
Systems of equations , polyno-
mial interpolations, statisti-
Cal analysis, heat transfer ,
electrical circuit analysis ,
animal population studies and
more.

Program cassette, users and
applications manual.

Send $25 check or money
order to:

MOPSY
P.O. Box 196
Glen Oaks, New York 11004

(N.Y. res. add $2 sales tax)

107

MEMOSHA: Allows the Sei-
kosha and Radio Shack printers
to list the entire ZX-TS
character and graphic set using
the Memotech Interface.

e Titled and page numbered

listings

eWorks with new as well as

saved program

eLine remembering routine

ARE YOU HAVING PROBLEMS
UNDERSTANDING THE MANUAL?

No problem. Understanding Sinclair Basic
is a newly developed learning aid which
displays and demonstrates 54 Sinclair
Basic commands. Basic program lines are
displayed and simultaneously run on a
split screen. Go as fast or slow as you like
because the program waits at each line
for your cue to continue. Repeat each
program as often as you like by pressing a
key. Written in machine language and
basic, Understanding Sinclair Basic gives
you a powerful tool with which you can
uniock the mysteries of Basic program-
ming. 16K required.

MISSING N

LINK NA included ($15.95)

VOXCOMP: Computer generated speech with
resident vocabulary permitting unlimited phrases
and sentences; allows the TS1000 to vocalize
instructions, answers, and messages - which can be
integrated into your programs (requires PARROT
Speech Synthesizer by R.I.S.T. Inc.) ($15.95)

SPECTREX: Creates true perspective drawings
from user defined data points; viewing angles may
be changed at will; data is entered only once and is
maintained by resident file manager ($15.95)

FINANCIAL MANAGER 1000; A completely
integrated business-home budget, expense, checking
and financial management system. Maintains
monthly and year-to-date records of 35 user defined
categories ($15.95)

INNOVA TION CAN BE SY BE R
FUN - ENQUIRE ABOUT
OTHER SYBER 1325 Diller Rd
SOFTW ARE Ocean Springs, MS

4 BER ace
(Masferbard VISA Phone: 601-875-3682
a METAR

$15. PLUS ONE DOLLAR FOR POSTAGE/HANDLING.
NEW YORK STATE RESIDENTS ADD 8% SALES TAX.
SEND CHECK OR MONEY ORDER TO A.-- ASSOCIATES,
175 FIFTH AVE., SUITE 3119, NYC 10010

A. Tt Associates

INSTANT LOADING! Tuus a Ie
A MUST FOR

Z.S.S. SINCLAIR

ET Mer NT COLD SHUTDOWN...
OWNERS =
1K- 64K You are a member of the Zoological Survey Ship Sinclair. So far you

have had a very sucessful mission, you collected many specimens on
many strange worlds. Many dangerous specimens. It was time to go
home. Everything went fine, coordinates were set, computer activated
and you along with the rest of the crew entered the Stasispod for a long
Sleep. Two months later the ship encountered an intense electro-
magnetic pulse. You awaken not to find yourself in orbit above Earth,
but in deep space. The life support units of the other crew members
have malfunctioned. But you are not alone, the specimens are loose!
Awakening earlier than planned, you are left weakened and
disoriented. The ship is laid out in the form of three wings composed of
modular units called Pods. Funny thing, but you can’t remember where
any of them are located. The creatures have managed to scatter the
equipment you need to help you survive and repair the ship. The reac-
tor is getting cold and you have to repair the five major Pods
(COMPUTERPOD, CONTROLPOD, NAVIGATIONPOD, FUSIONPOD,
LIFESUPPORTPOD), before it goes into COLD SHUTDOWN...

i x VERY USER FRIENDLY x 33 PODS RANDOMLY PLACED
| * EVERY GAME DIFFERENT x OVER THIRTY CREATURES
* EIGHT TOOLS AND DROIDS x 30 min - 1 hr. PLAYING TIME
x GRAPHIC DISPLAY OF SHIP, YOUR POSITION, SYSTEM STATUS
* TWO WAYS TO WIN: RESTART SHIP OR TAKE OFF ON
ESCAPECRAFT PHOENIX

8k ROM 16k RAM Supplied on cassette with instructions.
$12.95 postpaid Money Order or Check Made Payable to:
T.H. McCOMB.

THM SOFTWARE 154 Laconia Avenue, Staten Island, New York 10305
* x DEALERS ENQUIRIES INVITED x x

Easy to use BK EPROM PROGRAMMER. Housed in a slim lie flat case,
with ribbon connector and expansion slot for RAM packs etc. Uses
two 4K 2732 EPROMS in the 8-16K memory slot. It comes completely
assembled with instructions and software so you can load the EPROMS

with BASIC and/or Machine Code. Has zero insertion force sockets

so changing programs is as easy as cassettes. Load these programs
into RAM in less than a second. Result: Programs that fail-safe
load almost instantly. With one 4K EPROM; $64.95 plus $3.00 ship-
ing and handling. Additional EPROMS; $4.95 (WA residents please add

Sales tax).

MAV MICROPRODUCTS

BOX 31256
SEATTLE WA 98103

ss ce Speen sea tock) secs i eel oa S GENE US quM ce ESSE

CHIRPER module for your ZX81
or your timex/sinclair 1000.

The CHIRPER module lets you enter key-
board data fast and accurately. A sound can
be heard when a key is entered enabling you
to spot a missed entry or a double entry with-
out looking up at the screen. A buzzy-chirp is
produced when the key entry routine runs on
a 1 ora 2K machine. A large program in a RAM
pack produces a continuous tone that changes
on key entry.

A program can control the sound. Included
is a demo program that converts the keys into
a music keyboard of over two octaves.

The CHIRPER module installs easily inside
the ZX81 case with only three wiresto connect.
Complete installation instructions are included.

To order your CHIRPER send a check or
money order. We pay postage in the USA or
Canada.

AUDIOGRAPH CO.
3584 Leroy, Ann Arbor, MI 48103

MOTION PLATFORM
for
ZX81 and TS1000

*Computer not included

Program your ZX81 or
TS1000 to make it move
in any direction

Battery powered

No internal modifications
to your computer

Sample programs and
documentation included

Useful for robot projects
Only $299*

Make check or money order payable to:

BINGEL ROBOTICS
3540-244 SW ARCHER RD
GAINESVILLE, FL 32608

Please include $3.50 shipping/handling
FL Residents add 5% Sales Tax

*Computer not included

July/August 1983 9 SYNC

Tarbons Revenge
16K RAM. $10.95 pp.

An enhanced version of Spaceflash. Position
your space ship to intercept the alien with one
of your missiles. Select the number of ships that
must be shot down to win and the number of
ships Tarbon must land to conquer the earth.
As your aim gets better, Tarbon makes it more
difficult by sending down smaller ships.

MicroSync Software
Galaxy Master
1K RAM. Cassette: $4 plus $1 s&h.

Fight the aliens on the top; watch out for the
bombs that they drop. 3 levels of play. Machine
code.

Sikes Software
Moon Mission
16K RAM. Cassette: $14.95.

Land your space craft safely on one of the 4
launch pads. Features: Full graphics display of
mountain terrain, launch pads, and lunar cities.
Instrument panel assists you in landing safely.
Machine code.

Invaders
16K RAM. Cassette: $12.95.

Shoot down the marching aliens with your
rapid fire laser cannon before they take over
the planet forever. Shields are provided for
protection against the aliens’ bombs. Machine
code.

Casino Games

Biocal Software

(See Directory of Suppliers for prices.)
Blackjack

Multi-player, multi-deck version of popular
21 card game. Sharpen your skills for Las Vegas/
Reno.

Bong
Throw dice until you reach 10,000 points. 1’s
and 5’s are scoring dice. Up to 5 players.

Craps
Bet on the dice rolls. Up to 5 people.

Solitaire

Las Vegas version. Standout layout is dealt
with remaining deck dealt face up over last 6
columns.

Compuwiz Software
Casino Fun
16K RAM. Cassette: $10.

This very comprehensive Blackjack game fol-
lows full casino rules such as double down, split
a hand, etc. Hido is derived from the popular
English game. Excellent graphic displays are
used in both games. Watch the "chips" go up
and down as your winnings fluctuate!

Casino Fun II

16K RAM. Cassette: $10.

Play the exciting game of Baccarat as it is
played in European casinos. Graphics display
of cards, messages, and chips. Memory chal-
lenges and develops your ability to recollect.
For all ages.

TECHNI-STOCK SOFTWARE SYSTEM

HIGH PERFORMANCE SOFTWARE
for your ZX81/TS1000

6 reasons why TECHNI-STOCK SOFTWARE SYSTEM out

performs all other Technical Stock Analysis Programs.

1) Detailed price-volume charts on Logarithmic Grid

2) Sophisticated Statistical Analysis with Stock and Market
comparisons

3) Technical evaluations based on risk, return, moving aver-
ages and price momentum indicators

-4) Handsome binder with detailed instruction guide and

evaluation manual
5) Personalized Stock Data worksheets for your favorite 6
stocks and a market average
6) Unique system for preserving analysis evaluation in your
Techni-Stock binder
*for use with 16K or more
TO ORDER YOUR OWN TECHNI-STOCK SOFTWARE
SYSTEM just:
1. Fill in your name and address
2. Fill in the names of your favorite 6 stocks
3. Clip this coupon and mail to us
* Sorry no refund. However defective cassettes will be
replaced.
GENTLEMEN, PLEASE RUSH ME YOUR TECHNI-STOCK
SOFTWARE SYSTEM for only $34.95 plus $3.00 shipping
and handling TO:

OR JUST CHARGE MY:
C] MASTERCARD

Signature
MAIL THIS COUPON TO:

TOCO TECHNOLOGY

P. 0. BOX 98
SANTA CLAUS, INDIANA 47579

ECO-LOGIC
SIMULATION

THE DESPERATE
herd roams a hot tor-
rid plain, grazing on
the patchy brush, always seeking more until they
find it or starve . . . reproducing if only they can
eat enough. The rains come bringing thick
vegetation, but the herd's gluttony leads to a pop-
ulation explosion—then famine, and the beasts
starve in droves.

YOU control metabolism and energy require-
ments of the beasts and growth and food value
of the vegetation.

FAST ANIMATION by machine code and
RPNZL'M makes for nonstop on-screen action.
Beast in the Field TS1000 16K $14.95

METEOR STORM's fast arcade-style anima-
tion graphics bring the TS1000 the excitement
you thought you'd never see. Challenge yourself
to command your craft through a storm of inter-
stellar debris—your skills as pilot and gunner
will be stretched to their limits.

Meteor Storm TS1000 16K $7.95
Add $.50/tape p&h. CA residents add sales tax.
FREE catalog on request.

THE GOLDEN STAIR
141A Dore Street, San Francisco, CA 94103
(415) 552-1415

109

110

L&G Car-Comp Power Flat

e Use your Timex-Sinclair in your car

* Only 12V lighter outlet needed

* Permanent housing for computer/cassette
e Steady voltage prevents overheating
Vu-Load Monitor

e Insures program load

Level-Vu Prism

* For easy tape counter reading

Car-Comp 59.95 + 3.00 PH
Vu-Load 20.95 + 2.50P H
Level-Vu 2.95 + 1.00 PH

L& G Enterprises
Box 6854
Silver Spring, Md. 20906-0854
301-774-0126

(16K) ZX-81/TS-1000 SOFTWARE

YOUR KEY COLORS USING NUMEROLOGY
Each individual is unique! Learn by graphic
display-colors you emanate and character-
istic meanings.

SYNC INDEX (Menu driven)

Spending hrs. looking for an article in one of
those back issues? Program provides index
data for past 2 years. Search by 1 of 12
categories or by keyword. Displays subject,
volume date and page number.

HOUSEHOLD BOOKKEEPER (menu driven)

Enter the date. Displays all bills due for that
week. Up to 16 bills are graph displayed by
quarter selected. Maintains summary of
expenses paid, average cost, and expense as
percent of income. :

Printer opt. all prog. Sp.ZX or P40 Cassette
$9.95 ea. (incl. post.) Ca. tax. SASE for more
information.

I.M.S. ENTERPRISES

Box 4503

Lancaster, Ca. 93539

FREE
CATALOG!

Just let us know and we'll mail
you a FREE Creative Comput-
ing Catalog- 16 pages filled
with books, buyer's guides,
magazines, and more!

To get your FREE catalog,
write to: Creative Computing
Catalog, Dept. NE6F 39 East
Hanover Ave., Morris Plains,
NJ 07950.

Sikes Software
Blackjack
16K RAM. Cassette: $9.95.

Casino blackjack at its best. Take your $500
bankroll and put your luck to the test. Full
graphics display of cards makes this game fun
and exciting.

Maze Games

Biocal Software

(See Directory of Suppliers for prices.)
Amazing

Can the mouse reach the cheese before that
cat catches it? Watch the mouse travel through
the maze.

Catnmouse

Two cats chase a mouse through a maze. You
control the mouse to score on its way to the
cheese.

Maze. 1K RAM.
Shifting maze. Prints random maze.

Computer Software Associates
Mazeman
16K RAM. $14.95.

Mazeman scours the maze for food while
dodging ghosts which are trying to devour him.
Are you capable of beating the high score before
Mazeman is devoured?

Sikes Software
Micromaze
16K RAM. Cassette: $16.95.

Eat the dots and score points while evading
the deadly Drone; 11 automated levels of play,
so the better you play, the better this game gets.
Almost unbeatable. Machine code.

Other Games on the
Computer

Biocal Software

(See Directory of Suppliers for prices.)
3DTTT. Cassette only.

Challenge the computer in a game of Tic-
Tac-Toe. Played in 3 dimensions on a 4 by 4 by 4
grid.

8-Ball

Call your stroke, cue-angle, and object ball
angle. The computer calculates all subsequent
angles.

BCKGMN
Challenge the computer, play against another
player, or watch the computer play both sides.

Checkers
Challenge the computer to a game; includes
demo game and two player mode.

Cube-Sym

Rubik's cube simulator. Use any size cube.
How many moves will you take to solve it? With
scramble.

Stuart Software

Pick em

16K RAM. Cassette: $14.95 plus $2 s&h.
Predicts the outcome of NFL games with point

spread.

NBA Picks

16K RAM. Cassette: $14.95 plus $2 s&h.
Predicts the outcome of NBA games with

point spread.

SyncWare Co
NFLX Football
16K RAM. $9.95.

Provides a full-featured football contest for
one or two players. Not a "text" game. Safeties,
interceptions, runs, passes, punts, fumbles, and
field goals are displayed with machine code
graphics. Defensive plays include Blitz, Red
Dog, Normal, and Prevent. Includes demo
option to continually demonstrate pass and
running plays.

Game Collections

Charles J. Bonner
Flight Simulations
2K RAM. Cassette: $12.95.

4 flight programs; some with graphics. Guide
a parachute to a target; fly a biplane over a
mountain range; fly a jet airliner across the
Pacific Ocean; navigate a spaceship from the
Asteroid Belt to Earth orbit.

Computer Software Associates
1K Games. $19.95.

5 games: Duck Shoot: All the excitement of
duck hunting, without getting up at 4 a.m. Moon
Lander: If you thought Neil Armstrong had it
easy, this is your turn to try to land on the
Moon. Hangman: 1 or 2 players; sharpen your
spelling skills. Crossword: Challenging, mind-
boggling word association. Letter Square: Ar-
range the alphabet in correct order.

Compuwiz Software
Arcade Fun
16K RAM. Cassette: $10.

3 games: Arcade type; moving graphics.
Escape: Get as many points as possible before
the closing walls crush you. Snake: Devour
points, leaving a trail over which you cannot
cross. Trap: Two players are set against each
other.

2K Game Pack
2K RAM. Cassette: $10.

5 programs: Kaleidoscope: Dazzles you with
super displays. Over Under and Remember:
Two challenging and thought provoking card
games. Reverse: Explore your skills in logical
thinking. Sketch: Let your imagination run wild
and become an artist.

Mind Benders
16K RAM. Cassette: $10.

3 thinking games: Master Mind: An exciting
version of the popular board game. Super Mind:
A tougher version for those who enjoy a real
challenge. Guess: An enjoyable number guess-
ing game. All games use full screen graphics.

Florida Creations

Fun and Games Package

IK RAM. Listing: $1 plus SASE.

2K RAM. Cassette: $9.95 plus $1 s&h.

3 programs: Draw: Draw and sketch whatever
you want; automatic erase; flashing cursor.
Lunar Lander: Land you LEM on the landing
pad without blowing up; horizontal and vertical
velocities; fuel. Secret Code: Converts your
messages into an unintelligible string of alpha-
numeric characters and back into English.

July/August 1983 ? SYNC

NO MORE BAD CASSETTE LOADS
with
THE Z-DUBBER

The frustration of trying to load a cassette program into your Sinclair
ZX80/81 or Timex 1000, is this what you really bought your computer
for? Why put up with it? Now you don't have to. The Z-Dubber isa
small device which connects between your computer and cassette
player, improving your loading ease 100%.

The Z-Dubber also allows you to connect two tape recorders togeth-
er, to create perfect duplicates of your favorite cassette programs. The
Z-Dubber can be yours for $31.95 postage paid within the U.S. area.
Money back guarantee if not satisfied. Visa & Mastercard welcome.

BYTESIZE MICRO TECHNOLOGY
PO BOX 21123 - SEATTLE WA 98111
206-236-BYTE

SOUND with SINCLAIR:

MAKE AMAZING SOUND EFFECTS
WITH YOUR ZX 81, TIMEX
Sinclair 1000 or SPECTRUM

THE ZON x81 $49.95

e The ZONX SOUND UNIT is completely self-contained and especially
m designed for use with the ZX 81, TIMEX Sinclair 1000 and Spectrum

ee ; Computers. It just plugs in — no dismantling or soldering.
; e No power pack, batteries, leads or other extras. *
y s
ES e Manual Volume Control on panel — ample volume from built-in loud-
speaker.
e Standard Sinclair — 16K Rampack or printer can be plugged into ZONX
Sound Unit without affecting normal computer operation.
e Huge range of possible sounds for Games, Music, Helicopters, Sci-Fi.
Space Invaders. Explosions, Gun-shots, Drums, Planes, Lasers. Or-
gans. Bells. Tunes. Chords, etc., or whatever you devise!

e 8 full octaves. Uses 3-Channel sound chip giving programme control of
pitch, volume of tones and noise, all with envelope control.

e Easily added to existing games or programs using a few simple
“BASIC” lines or machine code.

e No memory addresses used — |.0. mapped.

FULL instructions with many examples of how to obtain effects and
the programmes, supplied. Fully guaranteed. British Made.

*Except with Spectrum, you need the Spectrum Extension Board Order
No. SE1 - PRICE $10.95 inc.

Payment may be made by Cheque. P.O.

Giro No. 388 7006. Postal Order or Credit

Card.

Export orders:- Bank Cheque. Interna-
tional Money Order. U.S. * or £ Sterling.

Dept. CG, P.0. Box 6 VISA accepted
25 63A, High Street Ring 0920 3182 for
weg immediate despatch.

WE HAVE WAYS
OF MAKING YOUR
2X81 TALK

THE ZXTALKER

® UNLIMITED VOCABULARY

® VARIABLE FREQUENCY

® SPEAKER & 500mW AMP INCLUDED
® INCLUDES SAMPLE SOFTWARE

® $9995

THE ZXPANDER

® USE 3 PERIPHERALS AT ONCE
® REDUCES WOBBLE $2495

CALL 1-408-248-0516 FOR DEMONSTRATION
SEND CHECK OR MONEY ORDER OR SASE FOR SPECS.
CA RESIDENTS ADO APPLICABLE SALES TAX

LLLI DIL LII III TIT
USER FRIENDLY RESEARCH
478 W. HAMILTON AVE. SUITE 154
CAMPBELL, CALIFORNIA 95008

INCLUDE 5% FOR POSTAGE EXTRA REFUNDED

ZX-MAN
Turn your ZX81I or TIMEX
SINCLAIR 1000 into an ar-
cade type game computer with
ZX-MAN. 100% machine
code makes this fast acting pro-
gram as much fun as being at
the arcades. With the joystick
option you can have the real
feel of game playing never be-
fore available for your ZX8l
or TIMEX SINCLAIR 1000.
16K required...... $14.95

JOYSTICK and ZX-MAN-Both for $24.95

JOYSTICK ||
With ATTO-SOFT's JOY-
STICK your ZX81 or TIMEX
1000 can be turned into an ar-
cade type computer allowing fast
controlover ZX-MAN and other
type software. Requiring only six
simple solder connections inside
your computer. Also included is
software to develop your own
programs............ $14.95

Send Check or Money Order to:

AT TO-S50FT

832 E. Third Street
: Galesburg, Illinois 61401
American (309) 343-4114 Please add $3.50

Express Postage and Handling
Accepted COD $2.00 additional

TEACHERS GRADEBOOK (32K)

— START THE NEW TERM RIGHT —
TRACK 40 STUDENTS/40 EXAMS. TESTS,
QUIZZES, QUARTERLIES AVERAGED AND
WEIGHTED; TRACK HOMEWORKS & PERFOR-
MANCE FACTOR: ADD/DELETE; ALPHABET-

IZING; SUGGESTED REPORT CARD GRADES;
REVIEW STUDENT/CLASS RECORD; PRINTER
OUTPUT; FULL SUPPORT; + MORE SELF

START/SELF SAVE/SELF NAME $24.95
dice SOFTWARE /P.O.B 2392/SECAUCUS,
.J. 07094

*** UNBEATABLE SOFTWARE OFFER ***

3 QUALITY CASSETTES FOR $12 + $2 S&H!!!
Included in these cassettes are BLACKJACK, MAS-
TERMIND, ESCAPE and 5 more games. All games use
excellent displays and run very fast. Send $14.00 to:

COMPUWIZ SOFTWARE
PO Box 390078, Mt. View, CA 94039
ORDER NOW!! SASE and get FREE MC program!

ON CASSETTE:STOCK OPTIONS $ 7.95
REAL ESTATE PLANNING $12.95
UAS BOX612 HADDONFIELD,N.J.08033

kkkkkkžkěžkžkkžkkkkkkkkžkkžkkkkkákkkkkkkkxkxk

*!i!!!Excellence in Performance!!!!*
ZZZEXZZZXZXZXZEZEEZEXZXZSZEXXZSZXZERSSZXEZEXESEXZEXXSXS
*"Cosmic Galaxian Arcade" ZX81/TS *
*Dennis A. Donovan IK yam *
*3125 Park Avenue Suite 11B *
*Bronx, New York 10451 *
*Check or Money Order Payable to *

*Name Above...... $1.00. Listing.
oe eoe oe oe ceo oe oe oe oe oe ox xe kx A xe x xA xA kx xA kx kx kx Xo kx kx k kk

IMPROVED HEAT SINK for ZX81 &
TS1000 eliminates system crashes
caused by overheating. $7.95
check/money order or BASE for
complete details to:

BASCO, 289 Baxter La, Milford
CT 06460

We are an organization of people using Timex/
Sinclair computers. We share information, pub-
lish a newsletter, and have a cooperative for com-
puter products which are discounted. Join us.

SINCLAIR USERS' NETWORK
2170 OAK BROOK CIRCLE /
312.934.9375

PALATINE IL 60067
STARTER PACKAGE
ZX/TS (1K)

This is a group of 14 programs to introduce the lan-
auge basic. These programs cover several topics
games, education & graphics) only $14.

Troiano Software Company
P.O. Box 40
Nesconset, New York 11767

AC CKT ANALYSIS FOR ZX81/TIMEX
1000 COMPUTE CKT FREQ RESPONSE
OF OP AMPS, TRANSISTORS, FETS, .
RLCS, TRANS LINES, OP/SHT STUBS,
REQS 16K MEMORY. INST & CASSETTE:
$9.95 PLUS $1 S&H PER ORDER.

P Computer Electronics Division

| P.O. Box 1332

amonati Monterey Park, California 91754

ee ee ee eee se I
Em um us um ms xu DE Gm um Gm um xd

"FLIGHT-PLANNER" for PILOTS

— maintains database of airports & VORs
—computes distance and true course
—corrects-course for wind and computes best altitude

of flight

—gene:ates enroute VOR checkpoints like RNAV
waypoints

—performs weight and balance

Send $10.00 to: Joe Smiley,
8A Anthony Circle, Newark, DE 19702

SyncWare Co.
Fun and Games I
2K RAM. $9.95.

5 games: Bring those TS1000s out of the
closet. Included are Syncwars, Minotaur, Nim,
ContsEntration, and TS Doodle, combining 2
older Basic games with 3 new ones in a “some-
thing-for-everyone” package.

ZXSystems Software

ZX -Pack

1K-16K RAM. Cassette: $16.99 plus $1.50s&h.
9 games and programs: Ranging from 4Dict-

tactoe to ZX-Probe and a savings account bal-

ance computing program. Instructions.

Horse Racing

CRC Software
Horse Master
16K RAM. Cassette: $12.95.

Before you go to the track...consult with the
Horse Master! Your racing form or local news-
paper gives you the date, and this program will
help you analyze it!

A. Doty
Horse Racing Handicapping
16K RAM. Cassette: $12.50 pp.

Analyses thoroughbred races giving critical
handicapping parameters for each horse. Based
upon statistical methods by using key past per-
formance information to aid in predicting po-
tential winners. Instruction pamphlet.

M. H. Marks Enterprises
Handicapper
16K RAM. Cassette: $9.95.

This program will help the horse racing fan
make more intelligent decisions at the wagering
window. After pertinent data obtained from
standard racing programs is entered, the com-

| puter assigns appropriate “points” to each par-

ameter based on a weighted system and a display
of the percentage of “chance to win” of each
horse in the field.

3G Company, Inc.
Horse Race Handicapping Program
16K RAM. Cassette: $24.95.

This is a scientifically derived system for
calculating odds on horse racs. Hundreds of
races were analyzed and numerical probabilities
computed to form the basis of this program.

UAS
Flat Racing. (C6001).
16K RAM. Cassette: $12.95.

Handicap the thorobred horses on any track.
Input data from the facing form and find the
racing form and find the potential winner. The
program follows the proven concepts used by
the Win-rator to find the most probable winner.

Hangman

American Micro Products, Inc.
Hangman
16K RAM. Cassette: $17.95.

A computerized version of the classic
children’s game of Hangman. Preprogrammed
with 235 words; however, the user can replace
these with more than 500 words.

Computer Software Associates
Lynchmob
16K RAM. $12.95.

A competitive game of skill and strategy for
2-6 players developed from the traditional game
of Hangman. Picks turns, keeps scores, and
lynches the losers in animated graphics.

Gladstone
Hangman (Z78)
16K RAM. Cassette: $9.95.

2 games. Movies: Over 100 titles and film
stars; 3 categories. Superheroes: Names and
their arch-enemies.

Haymarket Software
Haymarket Hangman
16K RAM. Cassette: $9.95.

5 categories with instructions on how to
change the category names to suit individual
needs. Each category contains up to 50 words
and the computer even adds the words you use
when playing with two players. In effect, the
computer learns. Increase your children’s vo-
cabularies or just put in their spelling list.

R. Midura
Hangman
16K RAM. Cassette: $10.

Features a graphics display, a scratch sheet
display to keep track of letters guessed, 7 word
categories, score keeping, and 400 word
dictionary (prerecorded dictionary: animals,
vegetables/fruits/herbs, music, astronomy,
birds, automobiles, and geography). Create your
own dictionary.

Softsync, Inc.
Hangman
16K RAM. Cassette: $14.95.

A learning tool to tutor children (ages 6-12) in
spelling. Seven versions of Hangman. Play
against the computer’s five prerecorded libraries
of categorized words (each word up to 17 let-
ters): animals, science, countries of the world,
states of America, and fruits and vegetables.
Create your own library of 500 words.

Z-West
Hangman
16K RAM. Cassette: $4.95 plus $1 s&h.

The computer becomes a very special vocab-
ulary tutor in this traditional game of Hangman.
Discover the unknown word before you are
hanged! 5 levels of play with 5 words in each
level.

Golf

Asia Tsusho Co., Ltd.
Golf Game
16K RAM. Cassette: $14.

A full scale golf simulation game of 18 holes
by adopting the table of random numbers sys-
tem. By inputting in sequence CLUB SELECT,
DIRECTION, STRENGTH, you can enjoy your
golf game with green scenery varied from time
to time.

Biocal Software

(See Directory of Suppliers for prices.)
Golf. 1K RAM.

Get your clubs out and play a few holes.
Good for judging distances.

July/August 1983 ? SYNC

USER FRIENDLY SOFTWARE
for the TIMEX/SINCLAIR 1000

Data-Manager (DM)
Screen prompted data collection sys-
tem with formula fields and both form
and spread sheet display

Finance-Manager (FM)*
Combines budgeting, record keeping,
and check reconcilement into one
operation

Program-Manager (PM)*
BASIC and machine code program
monitor and utility Functions include:
renumber, copy, delete, search, dump,
Hex load, Hex Debug, and a condense
mode that reduces program memory
size.

All programs are supplied on cassette with full
size instructions that are easy to read and easy
to understand. 16K required

$14.95 each postage included

VISA MASTERCARD or check

TOLL FREE ORDERS
1-800-543-3000 ask for
operator #520 item code*

COMPUTER ASSISTANCE INCORPORATED
PO BOX 3402 CINCINNATI OHIO 45201 / (513) 381-8778

SHELF CONSCIOUS?

Now you can organize your copies of

Now your magazines can be a handsome addition to your decor,

well organized, and easy to find, thanks to these durable li-
brary-quality cases or binders. They’re made of luxury-look
leatherette over high-quality binder board. And both styles are
custom-designed for this or any other magazine you save, with
size, color and imprint selected by the publisher. FREE transfer
foil included for marking dates and volumes.

e, For faster service, CALL

‘4, TOLL-FREE 24 HRS: 800-526-0790
æ (In NJ only: 201-540-0445)

| Please send: [] Cases [_] Binders

TITLE QUANTITY
Sync

Other qo aes eR IRI ae DD P ROME SEP eR
[ | PAYMENT ENCLOSED $1 25 Add

hold a year's issues on
individual snap-in rods,
combining them into
one volume. $7.98 each;
3 for $22.50; 6 for $42.95.

$1.00 per order for postage and handling. Out-
side USA add $2.50 per unit ordered; send US
funds only.

Mixed titles OK for quan- [
tity prices. [] American Express [ ] MasterCard
CREO ING GUAE a ee ate
Signature
Print Name
Address
City
store your issues for individ- A ;
ual reference. $6.95 each; 3 | pa ty x
for $19.75; 6 for $37.50. Mixed Residents of PA add 6% sales tax. id
titles OK for quantity prices. RE LE pete T DN NER NIGEL quede LM y BU, Ee

CLEVA computer War'e

ZX81 TS1000

ENTERTAINMENT PROGRAMS
SNAKEBITE Eat the snake before it eats you.

BATTLE Demanding game of military strategy
that can be played by 1 to 4 players.

STARSHIP TROJAN Pit your wits against the dangers of
outer-space and try to save your damaged

space-craft.
PRINCESS OF Face the monsters hiding in the
KRAAL underground and save the Princess.
STARTRACK Use photon torpedos to kill off the Klingons.

FUNGALOIDS Save civilization by bombing the ever-
multiplying fungus.

CRAZY-CARDS Totally addictive for cheats.
CUBE Use your computer to solve the mysteries
of the Rubik Cube.

TWO GAMES FOR THE PRICE OF ONE (ONLY $12.95)
All programs 16K

MACHINE LANGUAGE PROGRAMS
ASSEMBLER/ «x: V5 uuo opo RTL Que PE. $16.95
2 pass assembler written especially for the ZX81/TS 1000 (16K).
It is simply the best assembler available for those who wish to
write their own machine code programs. It is designed to run
alone, or together with the dis-assembler, and/or the de-bug-
ging program. These provide a system for writing, editing, check
ing and testing machine code programs that is second to none.

DISEGOEMBLERT 204. ear ny rS T REN RENE $16.95
Allows you to read the ZX81/TS 1000 ROM (16K) with the best
dis-assembler program available. It is written specifically for
Sinclair/Timex computers, and unlike some programs modified
from Intel 8080 dis-assemblers it gives full Z80 Mnemonics.

BEBO STA Ld REEL Ie ripe Duc $16.95
Makes writing machine code programs easier. Works entirely in
decimal. Therefore hexadecimal is not needed. (16K)

RROGSTORE/TODIUIgT PCR Ac MILL c. $16.95
Progstore contains a series of machine-code routines that cre-
ate 3072 bytes of user space and then transfer into this space
machine-code routines that allow the transfer of a BASIC pro-
gram into the user space after running this program allow a
return to another BASIC program stored conventionally in low
memory.

TOOL-KIT

Progstore toolkit contains four "utility" programs specially
written to operate from progstore. Having loaded progstore in
Toolkit can be loaded and then progstored with RAND USR
32500. Each program can be run by RAND USR 32723.

HEXLOADER- This program allows machine code programs to
be rapidly written in hexadecimal.

HEXLISTER—This program complements HEXLOADER by allow-
ing machine code programs to be listed in hexadecimal.

PROGMERGE LT. Cowon LL ouo. cee Se v d $16.95
Progmerge contains a series of machine-code routines which
allow BASIC programs to be stored whole or in part.
Please send check or money order. NO CASH!
New York Residents only add 814% Sales Tax.
SHIPPING AND HANDLING
Add $1.50 for first item and $.50 cents for each additional item.
Name
Address
City State Zip
Mail To: CLEVA Computer Ware
P.O. Box 2736
Brooklyn, N.Y. 11202 (212) 875-1207

GAME CASSETTES
TIMEX-ZX81 $14.95 EACH

“MONOPOLY” FAMILY GAME FOR
UP TO 6 PLAYERS-AVAILABLE IN
AMERICAN, SPANISH OR BRITISH
LANGUAGE VERSIONS. "WINGED
AVENGER? JHS1I- GOLD -SEAL

SPACE GAME. "SPACE TREK" NEW
RELEASE! SPACE GAME. “TRAD-
ER JACK” FANTASTIC FUN GAME-
BUSINESS LOGIC-SOUTH PACIFIC

LOCAL. “CASINO” INCLUDES PO-
KER-MACHINE, SUDDEN-DICE,
FIVECARD AND CHUCK-LUCK.
“TEN GREAT GAMES” INCLUDES
PACMAZE, GOBLER, ASTRO STAR
DEFENDER, VAMPIRES, SUICIDE,
MINEFIELD, FROGLER, STARTREK,
DICTATOR, BOMBER.

SAVAGE SOFTWARE PO BOX 441
TITUSVILLE, FL 32780

FROGRAMERS

Every Frograwer has written a
program someone else would buy,

We will package and promote your
usable programs and pay you a
competative royalty,

Send a description of your
program to our office. The sooner
you submit your work, the sooner
we can promote it for you !

SOPHIA SYSTEMS
15122 Fheasant Drive
Surrey, B.C. Canada, V3R 4X4

LEARN TO
PROGRAM

Text and File Organizers with
ZX DATA FINDER

A high capacity information

storage and retrieval tool for

16 K Timex and Sinclair Com-

puters.

Advanced file input and editing

routines are thoroughly

analyzed.

Comprehensive search and
display methods are fully
explained.

AN ADVANCED COURSE
IN DATA HANDLING

Free specifications are
available, or send $9.95 for
program listing and text to:

THOMAS B. WOODS
P.O. Box 64, Jefferson, N.H. 03583

114

Computronics
ZX Open
16K RAM. Cassette: $16.95.

Simulates golf on 5240 yard, par 71, 18 hole
course. Select driver, irons, pitching wedge, or
putter. Holes, slices, or misses the ball. Sand.
water, or lost in the trees. Up to 4 players.
Automatic score card.

Emvee Software
Mini-Golf
16K RAM. Listing: $6.

Play 9 or 18 holes against another player or
the computer. The better your practicing per-
formance, the better your practicing perfor-
mance, the more consistent your play will be-
come. A different course for each round
played.

R. Midura
18 Hole Golf
16K RAM. Cassette: $10.

Features a graphics display of each hole,
animated ball, 3 types of hazards, 5 player
capability, and final score card display. Hazards
include bunkers, water traps, and trees. The
display of each hole lists hole number, par,
current shot, current score, and name of player.
9 different courses available.

Minigolf
16K RAM. Cassette: $10.

Graphics display and random creation of each
of the 18 holes; random height of elevated tee; 3
types of variable size hazards; animated ball;
splash effect; final score report. Also displays
hole number, hole par, shot number, and current
score. Distance between tee and hole determines
par. Flashing messages for misses and hole in

one’s. Can play either same course or a new .

random course. 9 levels of difficulty.

Supplements for 18 Hole Golf
16K RAM. Cassette: $10.

Courses 4, 5, 6 on one cassette; 7, 8, 9 on one
cassette. Courses 8 and 9 feature unlabeled
graphics terrain items and more complex holes.
Courses 8 and 9 offer more terrain items per
hole and are recommended for advanced
players.

Mindware Inc.

From Eagle Sales
Graphic Golf
16K RAM. Cassette: $9.95 plus s&h.

A full 18 hole, championship golf course.
You face a brand new set of hazards each time
you tee up: trees, bunkers, and gusts of wind.
Make a choice of club (wood, iron, putter) and
strength of choice. You also aim the shot. We
do not promise that you will take the British
Open, but you will test your skill and judgment.
By Silversoft.

Sean Wilson
Golf
16K RAM. Cassette: $10.

Play golf with a full view of the course; nine
hole course; close up of green for your putt.
Superb graphics. For one or two players.

EZ Assembler and Editor
only $4.95 ppd.
Completely in BASIC. Enter it yourself
using the source listing supplied.
Accompanying documentation is an
excellent tutorial suitable for schools
or self instruction. The construction
of the EZ Assembler and Editor is
explained for those who would like to
know how it’s done, and to make it
easy to modify or enhance. 16K RAM!

BASIC program only,on cassette $9.95
Cassette & documentation $14.90

Eugene Zweig
P.O. Box 1022, Pearl River, NY 10965

MONSTER!

AWESOME GRAPHICS ! EXCITING 3D GAMES,

BUSINESS SOFTWARE, PROGRAMING AIDS,

WE ONLY STOCK THE FINEST IN SOFTWARE
FOR THE TIMEX TS1000, SEND SASE WITH
THIS AD AND RECIEVE A FREE GRAPHIC PRO-
GRAM AND A COMPLETE LIST.

Z X DATA

16783 BEACH BLVD, HUNTINGTON BEACH, CA 92647

CURRY COMPUTER
ZX81 and T/S 1000
Software & Hardware
Write for FREE Catalog

Over 60 Programs/Keyboards/Rampacks
DEALER INQUIRIES WELCOME
5344 W. Banff Ln./Glendale, AZ 85306
1-602-978-2902

AUT

MY TYPE teaches touch typing on your BIG ZX-81 KEYBOARD.
Features include key location, review, and token command
drills. Mistakes and W.P.M. are given at the end of each lesson.
: $8./16K cassette.

BIG-KEY LEGENDS are dry-transfer keycap graphics in red and
black that are identical to those on the ZX-81/TS-IOOO. For
standard 1/2" keycaps. $7./set (w/instructions)

Hn n

Daydesign, 79O E. Big Beaver, Troy, Mi. 48084

PALLLEEEEETTETTTETTTETTTTTITITTTTTTTTTEIT

WIM

Need a good setae to play or pro-
gram? Circle Chess board with in-
structions $5.00. Send your record-

ed Circle Chess games and pro-
eig for publication in Circle

hess Journal, Box 63, Des

Plaines, IL 60017.

| am selling Software for very cheap
prices: Call or write for free details:
914-969-7750 or

Robert Cannon

309 N. B'way

Yonkers, N.Y. 10701

Jerry and Neil nonbelievers

ARE YOU FOR SALE?

If you have marketable software let us hear from
you. If it meets our quality standards we could
make you a cash offer or suggest a royalty
agreement. If not we'll be honest and explain
why. Send for our SOFTWARE AUTHORS IN-
FORMATION GUIDE. It could be the
beginning...

ROBOTEC, INC., P.O. Box 55, Rossford, OH 43460

July/August 1983 ° SYNC

SOUND EFFECTS x MUSIC
& Two JOYSTICK - 1/0 PORTS

The ARCADE MASTER A&T $64.95
Plug-in Module for ZX81 and TS1000

Now you can create complex arcade quality sound effects, write melodies in 3 part har-
mony, & control the action with one or two Atari compatible joysticks (not included).

*3 tone generators - 8 octive range * Complete instruction manual and
*3 channel mixer, amplitude examples
controller, and envelope generator * Can be used with printer, 16K
* Noise generator rampak, and most other modules
* Internal speaker, volume control, and *2 Independent, TTL compatible I/O
audio output jack ports can be used as general purpose
e Requires no additional power supply input/output, or with joysticks

SPEECH MODULE The PARROT (yR.Ls.D $89.95

Generates 64 Allophones (Speech = Sounds) which you combine to
create any words, phrases, sentences, or sound effects you wish.

* Complete instructions & examples e Can be used with other modules
eSpeaker jack (drives 4 or 8 ohm e Compact, reliable, thoroughly tested
speaker) and safe

2 AMP POWER SUPPLY 2X80/81 «€ TIMEX 1000 « MICROACE

As you expand your system, you'll need more power to run it.

This supply has it! SPS-2A -- POWER SUPPLY -- $19.95

MULTIPLE OUTLET STRIP with built in 2 STAGE TRANSIENT ABSORBER
PROTECTS YOUR COMPUTER SYSTEM FROM DANGEROUS VOLTAGE SPIKES
Absorbes transients and surges such as those produced by lightning, switching surges
and noise spikes. 4 protected A.C. outlets, 15 A.C.B., power switch & pilot light.
6 foot cord TA4 -- TRANSIENT ABSORBER -- $29.95

MULTIPLE OUTLET STRIP ORGANIZE YOUR COMPUTER WORK STATION $19.95
Four grounded A.C. outlets, 15 amp C.B., power switch & pilot light. 6 ft. cord.

Haymarket Software

$each Total

QNTY
o uus omy — — ]| 1.95] V.
2

EI
BORNE
PONES
WERA
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C EE UA
MAZE-O-RAMA TEX WENN
ENT
BONES
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PRAE
d

Send check or money order to:

HURRICANE ELECTRONICS

P.0. BOX 237 * LANSING, IL 60438

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32238

000!-SL/1Q9-KZ

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INTEGRATED
DATA SYSTEMS

Audiograph Chirper $ 13:20
Bi-Pack ZON X-81 49.28
Kayde 16K RAM 51.28
Kayde 64K RAM about 112.00
Kayde Graphics Board 58.64
Q-SAVE 42.07

RIST Parrot (speech module) 90.30

Timeworks, Softsync, IPS and
others.

Graphicomp educational programs
on many subjects 11.92

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116

Just for Fun, continued...

impressive but require more programming
expertise, as anyone who has tried to
combine the relationships of PLOT,
PRINT AT, or TAB can testify.

HORTIIONTBHL ERE GREH

Spe

AE RSA E

ppp en pope aj
iO QUHDIOTU KO WO (HE UJ (CO 4)
:
Qua Oxon evo avec eua un

P OS fb G 10 00 ^]

(5) 7 ELSE EST fa

fed fort

The program cannot produce a com-
plete screen of full bars with only 1K, but
if the data is not 50 each time, the pro-
gram can be used with only 1K. To get
the most out the program, the prompts
can be shortened (or even omitted) and
line 10 can be deleted. Users with 2K
need not worry about memory because
the program and display is well under 2K.

Isosceles Triangle
Michael W. Schultz

This program will draw an isosceles
triangle, which is any triangle with two
equal sides and two equal angles. This is
done by drawing the base of the triangle
(lines 20-50) and then two ragged lines
starting at a fixed point and ending at
each end of the base (lines 60-100). These

lines are the equal ones and they form
two equal angles at the base.

Enter the program in Listing 1. Hit RUN
and ENTER in the SLOW or FAST mode.
To draw an inverted isosceles triangle
make the changes given in Listing 2.

Listing 1.
10 REM "ISOSCELES TRIANGLE”
15 REM DRAR THE BASE
3@ FOR X-10 TO S58
4@ PLOT X,iud

5 X
SS REM DRAW EACH SIDE TOGETHER
50 FOR Y=3@ TO 10 STEP -1

R Li
20 PLOT Y+t20.%¥
9o PLOT YvY.vY-40

Mandalas
Randy Adams

Type in this short program. It should
be RUN in FAST mode. Input values
such as 8, 10, 11, 13, 14, 16, 22, 26, 28, 31,
34, 35, 38, 44, 46, 47, 50, etc. Any value
from 1 to 100 will work, but not all of
them will produce symmetrical figures.
Try numbers 31, 32, 35, 38, and 26.

Randy Adams, 262 Edgrace Lane, Santa Cruz,
CA 95062.

(N^ZxPI),2zZ2-BD

Name Program
Jody Koenig

This program demonstrates a cute trick
which can be turned into a very useful
and effective teaching program with a
few additional lines. To use the program,
simply type in the program in Listing 1,
put your computer into SLOW mode, and
press RUN and ENTER. Add the lines in
Listing 2 for a spelling aid. With the
addition, you can input a word and go
through it one letter at a time by pressing
ENTER. The inverse letter makes it easy

Continued on page 118.

TIMEX 1000, ZX-81 (80)
O 8-Port 10 |

Interfaces up to eight
one-byte ports |

Accepts 16K RAM
10 $89

L1 ADDA :
2-channels A/D, 2-D/A "

Computer sensing and
control of (analog)
electrical devices (0-5V)

ADDA $89

L1 Beeper (Clock / Switch)
Programmable frequency tone generator,
clock (milliseconds to years)...

BCS $89

Each board comes with educational docu- Box 1140
mentation, applications, 2000 Center Street

ORDER

800-227-1617
operator 641

(CA, 800-772-3545
operator 641)

nd applicatio E

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Vo” 7x81
: KEY-TOP
SYMBOLS IN

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Original ZX81 symbols in Red, Blue and Black on White

background, covered with 7.5 mils of clear vinyl, and backed with
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The vinyl overlay is extremely durable, with just enough flexibility
to keep the original curve in the key top. When trimmed and
sealed per instructions, the edges disappear; the keys look and
feel like they were custom-made for your computer. (Caps may
be painted any color.)

Includes SHIFT LOCK, an extra FUNCTION/ENTER, and two
SHIFT keys in larger- sizes, in case you choose to use over-size
pads for these functions.

Complete instructions and diagrams for converting inexpensive
keyboards to customized ZX81/TS1000 consoles.

Money-back guarantee, of course.

$9.95

MULE Electronics
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444 Lincoln Bl. Venice, Ca. 90291

Please add $1.50 for shipping, and include 6% sales tax in California.

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OR send check or money order to:
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P.O. Box 733, Adelphi, Md. 20783

Add $2.00 shipping and handling for first cassette,
$1.00 each additional item. Maryland residents add
5% sales tax. Overseas orders add $3.00.

THE PEOPLE'S

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€ CONTROL CENTER-FOR T/S 1000, ZX-81-NO CABLE

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FREE JOURNAL

SINCLAIR owners send S.AS.E. to
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SINCLAIR ZX PRINTER PAPER
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Glendale, CA 91205

INDEXING AND MICROFORM

AVAILABLE
This magazine is indexed in THE MAGAZINE INDEX
available from Information Access Corporation,
404 Sixth Avenue, Menlo Park, California, and in
microform from Xerox University Microfilms, Ann
Arbor, Michigan and Bell and Howell, Micro Photo
Division, Wooster, Ohio.

"GALAXY"

Our best selling graphic space game — Abso-
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R.E. WOISH - 32F Plymouth Park - 1700 Butler
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ELECTRONIC CIRCUIT DESIGN

C.A.D. Software for Amps, Filters, pads, IC,
Antenna, regulators, more. 8K / 16K. 2 pro-
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/H, NY res. add $1.12 tax. Send $1.00 +
SASE for full details.
BOB DARIN
451 Center St.
Lewiston, NY 14092

$7.95 ZX-BATTLESHIP GAME $7.95
C.R.C. SOFTWARE
IT IS LIKE THE BOARD GAME, BUT ON YOUR TIMEX-SINCLAIR COMPUTER.
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MANAGEMENT AND FAMILY FUN. SINCLAIR - ATARI - VIC VERSIONS. 20%
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ORDER FOR INFORMATION AND CATALOG. LISTINGS AVAILABLE,
C.R.C —2901 AUBURN ROAD
AUBURN HEIGHTS, MI 48507

CLASSI

ATTN: 2X81 & TS1000 Game players!
Simple Illustrated Atari Joystick
Instructions. You only need a joy
Stick, no extra parts! Send only:
$3.50 to: EASY INSTRUCTIONS P.O.

Box 23582 Milw.,WI. 53223 HURRY!!

118

to see how a word is spelled, and it is
especially effective with young children.

Listing 1.

i9 PRINT “INPUT YOUR NAHE”
23 INPUT R$
S@ CLS

49$ LET RS(22 =CHRSE ((CODE Ai:
5 4328?

45 PRIN! AF iw Te

Sa FOR F=2 Ta ER AS ^

6@ LET A$í(F-1!)-CHR$ ((CODE As:
—-7-11)-1i1z8 ;

70 LET RH$iF)-CHR$ t: (CODE ASK?
i +1282

S@ PRINT AT 108,5;R3

ae NEXT F
19@ LET MS iLEN RH$)-CHR$ ((CODPDEz
a$(LEN Bs1!-128)
iid GaTa 35
Listing 2.

AT 10.95.n*5
42 INPUT US
75 INPUT Us
INPUT ü$

Jody Koenig, 1005 Mechanic Street, Decorah, IA
52101.

Glitchoidz report

A Machine Code Graphics Line-Drawing
Subroutine, 2:6.

Listing 3: Delete one INC HL at address
40A1H

Listing 6: Insert equals signs between
the letters and numbers in the LET state-
ments.

Making Backups for Machine Language
Tapes, 3:1.

Section 2. Copying with PEEK and
POKE.

The second paragraph should begin:
PRINT PEEK 16388+256*PRINT PEEK
16389...

In the third paragraph the SAVE dir-
ections should read: To SAVE, enter
GOTO 370...

A Small Business Payroll Program, 3:2.

Add to the menu routines the marital
status options: 1—single; 2— married;
3— head of household.

Math Support for Your ZX81, 3:2.
The alternate lines referred to in the
last paragraph are:
870 INPUT A$
880 IF A$—'" THEN GOTO 910
890 INPUT B$
900 GOTO 800
910 CLS
920 RUN
To superimpose graphs, add:
810 FOR X=-W TOW
830 INPUT Y
To improve response to the menu:
40 LET A- VAL INKEY$*150
50 CLS
60 GOTO A

Minotaur, 3:2.

Enter the list of variables in the im-
mediate mode (i.e., without line numbers;
e.g., LET A=1). A through I=1; J=512;
K-—16396; L=33; O20; P=1; Q=2; R23;
$—5; T=20; U=31; V=128. Check by

pressing PRINT (variable letter) and
ENTER. Do not use RUN or CLEAR since
these wipe out the variables.

To start type GOTO P; when the cursor
appears, enter the density (0-1; try .35).
To restart at the same density, type GOTO
T. To set up the same maze again, press
BREAK (except when entering density),
type in RAND n (n = a number from 1 to
16535). Use the same number to repeat
the maze. After the RAND command, type
GOTO T to start. At density .35, RAND
19, RAND 20, and RAND 40 ‘produce
challenging mazes. The author would ap-
preciate reports of “good numbers”; be
sure to include the density setting.

Knowing Your Strengths, 3:2.

The author comments:

One of your astute readers in translating
the program into TRS-80 Basic caught an
unnecessary negative and a flow error
which gives spurious results when attempt-
ing to RECALCulate new section or ma-
terial sections. Make the following cor-
rections:

Changes:

1545 IF N=4 THEN GOTO 2050

2140 LET S2=(W*L)/6*Z)

1545 corrects the flow and 2140 eliminates
the unnecessary negative.

Add:

3005 IF N=4 THEN GOTO 3020
3035 IF N=4 THEN GOTO 3050
3075 IF N=4 THEN GOTO 3090
These skip the W, L, and X1 inputs.

Eliminating the printout (line 1622) will
save screen space.

To eliminate unnecessary, screen con-
suming decimal places change:

3505 PRINT “... PT.)=”; INT
S2;“#PSI”

Some additional output I have found
helpful:

3515 PRINT “STRESS=”; INT (100/(S
/32));“#PCT. OF YIELD”

July/August 1983 ? SYNC

Get the
most from
: your

coa

. Timex
Sinclair
or
Sinclair —
computer. —

Here’s the best from Sync,
the exciting magazine devoted
to Sinclairs!

he Best of Sync is a collection of more than 80 of the

most valuable articles, programs, tutorlals and re-
views that appeared in Volume One of Sync, the magazine
for Timex Sinclair and Sinclair owners.

This information-packed book is a vital resource for
anyone who'd like to get more work (and more fun!) from
a Timex Sinclair 1000, a Sinclair ZX81 or ZX80, or a
MicroAce computer. Topics covered include:

e Games
Mathematical applications
Graphics techniques
software programming
Translation
Machine language hardware
Resource listings
Product reviews
e Complete glossary

In The Best of Sync you'll find game programs like
"Forest Treasure" and "Motorcycle Race Game’’...hard-
ware plans for a "Key Click Generator" and a “Parallel
Interface”... programming features on “Handling Charac-
ter Strings in the ZX80,” "Converting from Other BASICs"
and "An Introduction to Machine
Code.’ And that's just a small
sample.

These ultrapractical fea-
tures appeared in issues of Sync
that are now out of print and
nearly impossible to find. But
you can still make use of
the important information,
techniques and programs
they contain—by ordering
The Best of Sync today!

Also available at your local

bookstore or computer store. 8%" x 11", softcover.

For faster service, PHONE TOLL FREE: 800-631 -8112

(In NJ only: 201-540-0445)
CREATIVE COMPUTING PRESS

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Please send me _________ The Best of Sync, Volume One, at $9.95* plus
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2-BIT" SOFTWARE, P.O. Box 2036
Dept. SN2, Del Mar, CA 92014
(619) 481-3629

ADCHMOHSEPIBE Du o CIR hospes lah eod cd Rao bos] qune coe scena Tues 118
J.T ho MXN AE wr NS ME T PEANT ENE SEC iE C CUR toan PP MAE E E 46
Ad VASE PART otl Pure idi vins cc Fenpgcubosene Us vasi T 108
Apropos : Dechnolgy. i 2. Locris parar dose dea paar Fed nnkodosagueE en 11
Atto. SQ WIFe. x acid Peres ee antea i Ce cet C unde R Vn Popup Ub qa 111
ADOOS RWV qe Jes tide aka ko ota S eber TE cu veg 109
B DANON: BOOREIIBE ee recor ced caeci eo sa Peter e à 38
Ere Beck ore ar aia Bene S edo aitdrus veg age Gu dno y) 118
BOB BOTORS A coarse et hs ieget nentisersabr N TRAE cda 37
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Básco (Biase SUBSODE) rii S vs eedue Cyan nd peo AES Neu ape enu ac cto an 112
Bonnie & Clyde SO[DWRES. oS uds qe gak fooeuri a cele Vi Rav a «e dua) 79
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Business Management Specialist............................... ss. 45
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Byte Back uq eee cp e AU CORRI cata gn ens teo AR Fl aeta spa 99
Bytespit PEOUUCU iae aure rA ttr tapas eden fo ense Pe apa Leto 111
Robert Cannon xu. 0 oetra e Creo ae REOR Teen 114
CEDICODICS eor quede caus cade duets debo du liso aM) cpasudan és ever a CR Va pdt 17
Circle Ae CER, Krss cca de ditus t ie eiie disce citare luce FRE dE cs ade 114
NEVE ACME Ware ieri RS. ieaS an G aera 113
Cobra Pal Lida A VIN age Noise air rett 41
Compiler ASSISA A a aari Aa 113
Compuler CONTU ose eed aosa ae n hiaai 78
Computer Engineering Services ......................... eese 116
Fhe C Omputer TTRQOEE 1 ILI e Leod erne diosa Npa einem 85
Computei- Melt SOL DWIEE au. ro cie anri oe ctas ro ceto De ag coda septo seetn 14
Cm mide oni e acecveu guess casts sbobcdube Dia ts op ecu ds eiu dni etr iid TS
COmmUWIZ SONWALE: Aa eak e aek A o eaa tace 112
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Bob Darin: (formerly Bob Sye ehin. assise 118
Date estu. AS od (E PRAE Irene Hines TE eiii Cover 2
TUO ri nee x pirate ad Up Re ES A Niuenesusngas 83
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MMO E IE a AA o odas A TT A E PONAS 85
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DOR ERE LEGO cs dk ora ence ve eco T Qus sata 1
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B. Anhur Brown COE ng A que iu qp pto pato Teneo a 106

. PLUGIN SOFTWARE

PROGRAMMERS TOOLKIT and on PLUG IN CARTRIDGE $29.95
GRAPHICS ROUTINES 16K-64K COMPATIBLE
A cartridge that plugs between your ZX/TS and your RAM PACK, printer, etc. The
toolkit portion contains commands that will: RENUMBER, DELETE, GENERATE,
SHORTEN, by DUMP is in FREE, SEARCH AND REPLACE E Strip in. The graphics

commands

include: UPSCROLL, DOWNSCROLL, LEFTSCROLL, RIGHT

SCROLL, INVERT SCREEN, FILL SCREEN, tum BACKGROUND, DEFINE. The
cartridge uses the normally unused 12K to 16K block of memory so that it uses none
of your valuable BASLIC programming area. ADD $2.00 POSTAGE & HANDLING.

CASSETTE SOFTWARE

MORLOC CASTLE: 16K Ram ZX81/TS1000 $14.95
Similar in styleto DRY GULCH, MORLOC CASTLE is, however, written in machine
language to provide much faster response. Estimated time to solve is 30-50 hours.
MORLOC CASTLE provides over 200 words of vocabulary, is SAVEable in prog-
ress and uses every last BYTE of RAM. VERY DIFFICULT (HINT SHEET

AVAILABLE)

DRY GULCH: 16K Ram ZX8/TS1000 $9.95
DRY GULCH is an interactive adventure where the user/player types in short
English phrases such as: Go North, Take the Hammer, Saw the Iron Bars, etc. to
explore a deserted old west ghost town and search for treasure. It is written in BASIC
and is saveable in progress. Estimated time to solve is 10-12 hours. TRY THIS

ADVENTURE FIRST.

PROGRAMMERS TOOLKIT and 16K RAM ZX/TS $12.95

GRAPHICS ROUTINES

The same program as supplied don plug-in cartridge (see other side) except this
cassette loaded program needs RAM in the 12K to 16K block (such as available
from HUNTER PRODUCTS or 64K RAM packs).

KITS & PLANS

1/0 ports and EPROM programmer for ZX81/TS1000 (plans) $5.00
Schematic documentation, and software listing to build a 24 line I/O port then use it
to program: 2716, 2732, 2732A, 2764 EPROMS.

EPROM CARTRIDGE KIT $16.95 :
Kitincludes all parts necessary to build a plug in cartridge that will accept 2716,
2732, or 2764 EPROMS. Board may be memory mapped in 4K or 8K increments
anywhere from 0-16K. The board accepts one EPROM and the memory mapping is
jumper selectable. EPROM not supplied. DEALER INQUIRIES INVITED AND

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QUANTITY DISCOUNTS ARE AVAILABLE.

ALL PRICES INCLUDE POSTAGE & HANDLING EXCEPT WHERE NOTED (NEW
YORK RESIDENTS ADD SALES TAX)

UPSTATE LABS
27 ELVIRA ST.
ROCHESTER, N.Y. 14606

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Education, Business, Entertainment . . .

| Wr n w
-— Seven New Programs ~~
|- For the Small Business _

DV Qu i d M E E g S
; / e Customer Credit File - < :
* General Ledger a
* Ecucu-Diary eae)
* Exec-Address & Phone File |
* Accounts Payable
* Accounts Receivable ee

/ mee. Inventory

s up
"m

* e

VALMIT" uz

lable at Your Local Retailer ORBYI E

for r
M The Creative Force

mex Sinclair 1000 e. Sinclair ZX81 P.O. Box 948, Waterbury, CT 06720

203-7 53-8308

Meet the Banana," the very
tough, versatile, portable, and
reliable dot-matrix printer from
Gorilla?"

At $249.95 retail it's an ideal
and inexpensive companion for
personal computers like Apple”
(or Apple*look alikes" such as
Franklin® or Albert^), TI? i
Commodore? TRS-80; Kaypro;
Timex? Osborne? etc.

After that, it's merely com-
parable to other printers that can
cost up to three times as much:
10" carriages (to handle standard
91/5" ARDET] 80 columns, graphics
capability, 10 characters per inch
(expandable to 5 cpi) draft-quality
print (for perfectly acceptable
form letters, data processing,

BUY A BANANA. SAVE A BUNCH.

business reports, etc.) tractor
feed (for precise alignment and

.quick loading), parallel or serial

interface (take your pick), self-
inking ribbon cassette (for long
life and easy installation), 10
portable pounds in weight, and
compatibility with so many of the
most popular personal computers
on the market.

Plus its printhead features a
unique single-hammer design that
eliminates a lot of moving parts, to
eliminate a lot of annoying repairs.

That's the Banana: silly name,
serious service. It's everything
the expensive dot-matrix printers
are...

Except expensive.

Leading Edge Products, Inc., 225 Turnpike Street, Canton, Massachusetts 02021
Toll-free: 1-800-343-6833; In Massachusetts (617) 828-8150. Telex 951-624.

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